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This page contains brief summaries of all Lessons in the Main Story.
We are pleased to inform you that you have been accepted at the Royal Academy of Diavolo.
Please return this letter with your sign to confirm your participation.
We are looking forward to welcoming you as part of our new exchange program.
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This tale starts with a dream... your dream.
Please help me. I was locked up by a demon.
You are my only hope, help me get out of here.I beg you, you must find me."
You hear the distant voice of an unfamiliar man and wake up to find yourself in a place that looks like a courtroom. The stern voice of the man in the seat of the chief echoes.
"We welcome you, human, to the demon student council."
You are selected to become a student at RAD, a school for demons.
Awaiting you are seven demon brothers each with their own peculiarities...and a mountain of tasks?!
There is only 1 rule you have to remember...One Master to Rule Them All!
In a place that looks like a courtroom, MC is confused to suddenly find themselves being welcomed to the Devildom by a man who introduces himself as Diavolo. He goes on to explain he is "the ruler of all demons" and that MC has been brought to the Royal Academy of Diavolo, aka "RAD."
Diavolo then introduces Lucifer — his right-hand man and the "Avatar of Pride" — who explains that MC has been chosen as a representative of the Human World in Diavolo's exchange program, which is a program intended to strengthen the Devildom's relationship with the Human world and the Celestial Realm. As one of the four exchange students joining at RAD, MC will stay in the Devildom for one year while working on school tasks. Lucifer then gives MC a D.D.D. — which functions nearly identical to a smartphone — and tells them to call his brother Mammon with it.
After the phone call, Lucifer introduces his other present brothers: Asmodeus, Avatar of Lust and fifth oldest; Satan, Avatar of Wrath and fourth oldest, and Beelzebub, Avatar of Gluttony and sixth oldest. Diavolo then tells MC they'll be saying with Lucifer and his brothers in the House of Lamentation during their time in the Devildom. Mammon, the "Avatar of Greed" then arrives, and Lucifer informs him that he will be in charge of watching over MC, which Mammon agrees to only after putting up a fight about it.
Lucifer tells MC their task at RAD is to "polish up your soul" and "acquire the power to resist demons." At year's end, MC will also be required to write a paper about their stay in the Devildom. However, as MC has no magic, he and his brothers will lend MC their powers via special cards summoned using the Nightmare app on their D.D.D. and used in dance battles. With his explanation complete, Mammon takes MC to the House of Lamentation, which acts as the dorm for RAD student council members, except for Diavolo, who resides in a castle instead.
Once inside, Leviathan, the "Avatar of Envy" shows up. He demands Mammon pay him back the money he owes, to which Mammon uses MC as a distraction before running off. Leviathan then gets an idea, and drags MC to his room. After rambling for awhile about The Tale of the Seven Lords fantasy novel series — aka "TSL" — and introducing MC to his goldfish Henry, Leviathan tells MC that he want the money back he gave Mammon. However, he can't force him, because Mammon is the second oldest brother while Leviathan is the third, meaning that he's weaker than Mammon.
Instead, he wants MC to make a pact with Mammon, which would mean he'd have to do whatever MC told him, including giving Leviathan his money back. Traditionally, humans entering pacts with demons offer their soul in exchange, but to avoid trading their soul, Leviathan plans to have MC offer something "he'd do ANYTHING to get."
MC has their first day at RAD, where they encounter Solomon, who introduces himself as the other exchange student from the Human World. He hands MC their D.D.D. before departing. MC then runs into Lucifer, who warns them that Solomon cannot be trusted, and that he not only "wields powerful magic," but also has a Ring of Wisdom that aids him in controlling demons.
Going on what Leviathan told them yesterday about Lucifer having Mammon's credit card, MC tries to get a hint from Lucifer about where he hid it. He mentions having "frozen" something of Mammon's, then the bell for the next class rings, and the two part ways.
Meanwhile, Solomon, Satan, and Asmodeus are playing cards and discussing Mammon. Satan comments that he heard from Lucifer that MC is trying to make a pact with Mammon, and has "teamed up" with Leviathan with this goal in mind. According to Satan, Lucifer also said he gave MC a hint about the location of Mammon's credit card.
That night, back in the House of Lamentation, MC receives a chat from Leviathan asking them to come to the kitchen. They encounter Beelzebub there, and ask about the seventh brother they've not seen. Beelzebub doesn't tell them anything, and tells them not to ask his other brothers either, because Lucifer would be angry.
After Beelzebub leaves, Leviathan comes out of hiding. He looks for Mammon's credit card in the freezer, and finds it frozen in a block of ice, which he puts into the microwave to thaw. Mammon then enters the kitchen to sees his card — which he's named Goldie — and begs for Leviathan to return it to him. Leviathan will only agree if Mammon makes a pact with MC, to which Mammon agrees.
In the Dining Room he next morning, Asmodeus and Satan talk about how amusing it is that Mammon now has a pact with MC, and how interesting it is that Leviathan helped them. Mammon enters and starts yelling at everyone for treating him poorly, then blames the whole situation on Lucifer and insults him, not realizing Lucifer had entered the room as well. Lucifer hits Mammon, then compliments MC for having made a pact with him.
Mammon drags MC out of the room, complaining that bad things have been happening to him ever since MC's arrival. After he threatens to eat MC, they use their pact for the first time, telling Mammon to "stay!" Mammon freezes in place, unable to move due to the pact's magic.
Later at RAD, MC is introduced to Barbatos — Diavolo's steward — as well as Simeon and Luke, who are both angel exchange students from the Celestial Realm. After both Lucifer and Diavolo tease Luke by calling him a "chihuahua," everyone save Luke and MC leave for the next class. Luke takes this time to warn MC to "never trust a demon. Especially when that demon is Lucifer."
That night, MC thinks they hear someone calling for help. They leave their room and follow the sounds to the stairs of the attic, where they run into Lucifer. He warns them that the attic is dangerous for humans, and instructs them to return to their room, which they do.
It's another night of MC being unable to sleep at the House of Lamentation, so they try again to reach the attic, and again are stopped at the staircase by Lucifer. In the Dining Hall the next morning, MC asks Mammon what it at the top of the stairs. He initially refuses to say anything, but after some goading, he relents.
He tells MC that Lucifer has an interest in the vinyl soundtrack for The Tale of the Seven Lords. If they can get the soundtrack from Leviathan and give it to Lucifer, that should distract him so that MC can climb the attic stairs. MC asks Mammon to help them, then make use of their pact with him when he refuses.
The two go to Leviathan's room, and are surprised to encounter Solomon in the hallway. He tells them Leviathan invited him to his room, then knocks on the door. He then says a secret phrase related to TSL trivia beginning with "The second lord..." and is allowed inside. When MC tries using the same secret phrase, however, it doesn't work due to the phrase being "periodically reset." Mammon decides this means MC will have to learn enough trivia about TSL for Leviathan to let them borrow the soundtrack.
MC then has a "TSL Full Series DVD Marathon Night" with Mammon and Beelzebub, who is there for the popcorn. They learn in DVD Volume 2 that the Lord of Fools' former sweetheart's name is "Geldie," in Volume 5 that supplies the Lord of Fools sent the Lord of Flies' country had spoiled, and in Volume 7 that the other lords can't free the Lord of Emptiness from his tower because they were afraid of the Lord of Corruption.
The next day, Mammon quizzes MC to make sure they remember this information, the Leviathan shows up. MC challenges him to a competition to see who the bigger TSL fan is, and eventually goads him into agreeing. Later at RAD, both Satan and Beelzebub give MC advice on how to defeat Leviathan. Mammon later agrees with what Beelzebub said about trying to make Leviathan jealous to throw him off his game, but warns that if they succeed "there's no guarantee he won't kill ya."
MC can either ask "a human" or "an angel" for advice on how to make Leviathan jealous, and then it is time for the "Devil's Trivia Showdown." The judge for the competition is Diavolo, Asmodeus is the host, commentary will be given by Satan, and the "guest demon" is Beelzebub, which was paid to be there in cheeseburgers.
The showdown begins, and MC is given easy questions, such as listing the first three lords in order of age — said order being "Corruption, then Fools, then Shadow" — while Leviathan is asked questions such as what is written on page 724 of TSL Volume 3. Despite the difficulty gap, Leviathan still manages to answer every questions he's given correctly. In response, Mammon urges MC to play their "trump card."
To turn the tides of the TSL competition in their favor, MC reveals their "secret weapon." If they chose to ask an angel for advice in Lesson 3-17, MC summarizes the plot of the still unreleased TSL Volume 9, as was told to them by Simeon. Their words are confirmed by Diavolo, who is capable of telling "whether someone is telling the truth," as explained by Satan.
If MC chose to as a human in Lesson 3-17, they reveal a pendant loaned to them by Solomon in the shape of a single wing. This is the platinum version of the Lord of Corruption's lost wing pendant, which is an extremely rare item of TSL merch.
Whichever option was chosen, the advice pays off, and pushes Leviathan into such a fury that he turns into his demon form and charges at MC. He is stopped, however, by Lucifer also taking his demon form and defending MC. Lucifer then orders Leviathan to return to his room and calm down, which he does. Diavolo then announces the competition to have ended in a draw.
MC managed to fall and sprain their wrist in all the chaos, so Mammon joins them in their room and tries his best to bandage it. Beelzebub is also there, which Mammon complains about, but Beelzebub rebuts that Mammon is in MC's room so often he's even left a phone charger and toothbrush here. He then heads to the kitchen for a soda, leaving Mammon alone with MC. He then tells them that he — and no one else — has to be the one to save them next time, and that if he can't save them, "then make sure you die."
MC gets a chat from Leviathan, and leaves to meet him in the Planetarium. While they're gone, Mammon snoops around their room looking for things he can sell. He then talks about being willing to sell even MC if there was profit in doing so. Beelzebub calls his bluff, stating that Mammon likes MC too much to do that. Of course, Mammon frantically denies that claim.
In the Planetarium, despite Diavolo declaring the TSL competition a draw, Leviathan still makes a pact with MC. MC then asks him for the vinyl soundtrack for The Tale of the Seven Lords, and heads for Lucifer's room. Once invited in, they give Lucifer the soundtrack, who then tells MC he will now spend the evening listening to the soundtrack and not leave his room, but reminds them that the stairs to the attic are still off-limits.
Naturally, MC takes this opportunity to climb the stairs anyway. At the top, they see an obstructed doorway, behind which is the person whose voice MC has been hearing calling for help. This person claims to be a human, and tells MC that Lucifer locked him here in the attic. The door is sealed with powerful magic that only the combined magic of Lucifer and all six of his brothers can break. So, the stranger tells MC they have to make pacts with all of them, and that their next pact should be Beelzebub.
The next morning in the Dining Hall, Lucifer asks MC if anything happened last night, then admits he allowed MC to visit the attic, and advises them to forget about that, and focus on surviving the year in the Devildom.
Later that night, MC is in their room when they get a chat from Mammon asking them to meet him in the kitchen. When they do so, Mammon pushes them into eating a custard belonging to Beelzebub. Beelzebub then arrives, enraged because he thinks Mammon ate his custard. He turns into his demon form, and charges at Mammon.
MC, Mammon and Beelzebub are brought to Lucifer's where he lectures them on what they had done wrong. The kitchen has been destroyed after Beelzebub went on a rampage, and since MC's room was adjacent to the kitchen, their room now lacks a wall. Lucifer tells them that MC will be staying in Beelzebub's room for the time being, despite Mammon's objections.
There are two beds in Beelzebub's room; the left belongs to Beelzebub, and the right belongs to Belphegor, Beelzebub's twin brother. Beelzebub tells MC that Belphegor is in the human world as an exchange student along with another demon named Diaval. He also tells them the brothers used to have a sister named Lilith who had been especially close to Belphegor and him. MC later realizes that the occupant of the attic room is actually Belphegor when they find a portrait of him in the portrait room. That night they return to the attic to confront Belphegor, who admits the truth.
The next morning, MC eavesdrops on a conversation between Lucifer and Beelzebub, and learns that the demon brothers were originally angels in the Celestial Realm, but after ending up in the Devildom Lucifer pledged his loyalty to Diavolo. They also learn that there is tension between the brothers due to Belphegor having attempted to stand in the way of Diavolo's dream. MC decides to help Belphegor in order to resolve this conflict.
Later on, Luke messages MC that he's outside the House of Lamentation and he needs to spend the night in MC's room. As MC's room was destroyed by Beelzebub, Luke has to stay with MC in Beelzebub's room. During breakfast, both MC and Beelzebub eat less than usual, wanting to bring food back for Luke. Beelzebub having uneaten food left on his plate causes a commotion between Mammon, Satan, and Asmodeus. On the way back to Beelzebub's room, he and MC find Luke roaming the hallway and looking inside other rooms because being stuck in Beelzebub's room is boring.
Back inside the twins' room, Beelzebub announces that Lucifer is conducting a surprise inspection. He shoves Luke into a closet to hide him, but when Lucifer arrives and orders the closet to be opened, Luke isn't there. He's still gone the next day, though MC and Beelzebub hide this from Simeon when he asks them to take care of Luke until he's ready to come back to Purgatory Hall. Beelzebub and MC search the house but still can't find him. When they reach the entrance hall, they notice the decorative dollhouse of the House of Lamentation has an extra room in it; a room that doesn't exist.
MC and Beelzebub find a secret room that is a copy of Lilith's room back up in the Celestial Realm. When MC asks Beelzebub to tell them more about Lilith, he describes what happened during the Great Celestial War. Mammon suddenly calls MC and tells them to hurry to the underground tomb, which is where Luke is. Lucifer found him there, and is furious at the sight of Luke holding a grimoire. When MC and Beelzebub arrive, Luke accidentally admits Beelzebub hid him in his closet. Lucifer doesn't give Beelzebub a chance to defend himself, and warns that he and Luke should get ready to face the consequences.
MC decides to step between them, shielding Luke and Beelzebub. A furious Lucifer tells them that they can only save one of them. However, MC says they want to protect both. Outraged by MC's reply, Lucifer prepares to attack MC just as everything fades to black. Later, MC wakes up back in the twins' room to Beelzebub calling their name. They ask what happened, and Beelzebub explains that Diavolo arrived in time to stop Lucifer. Simeon took Luke home, who was shaken up but not injured. Beelzebub is also uninjured.
Beelzebub tells MC that he's the one to blame for what happened before, and asks MC why they tried to protect him and Luke. MC either tells him they acted on instinct or that Beelzebub and Luke are important to MC as they're friends. Beelzebub tells MC he wants to do something for them as a thank you, so MC asks him to make a pact with them. Beelzebub asks why to which MC replies they want to impress Lucifer so they help him make up with Belphegor. Beelzebub agrees that he also wants the two of them to make up.
He later takes MC to Hell's Kitchen to eat, but Mammon and Leviathan tag along. MC explains to all of them why they to make a pact with the brothers, and Mammon and Leviathan decide to help. When they return to the House of Lamentation, Lucifer appears and tells MC that their room has been fixed. On the last night staying in Beelzebub's room, he has a dream about Lilith that's different from the nightmare he usually has.
The next morning, breakfast with the brothers is awkward and uncomfortable. Just as MC is about to head off to class early, Lucifer tells them to meet him in the music room. A conversation occurs and Lucifer apologizes for his actions. Shortly after, in the student council room, Diavolo makes the announcement that there will be a retreat held at the Demon Lord's Castle.
Everyone gathers in the entrance hall to get ready to leave for Demon Lord's Castle. Mammon tells MC that there are scary rumors about the castle, like there being an underground labyrinth, but Lucifer interrupts the conversation. He hurries everyone along, as he wants to get to the castle before the angels and Solomon do.
They do manage to arrive to the castle first, where Diavolo and Barbatos greet them. Solomon, Simeon, and Luke arrive shortly after. When the younger angel spots MC, he hugs them, saying he's really sorry about what happened back in the underground tomb. Barbatos then begins to explain how the retreat will work.
First, there will be a tour of the castle to learn about Devildom history, and then Devildom food will be served made by himself. The next day will have a scavenger hunt, food from the Celestial Realm will be made by Luke, and finally there will be a dance held. On the final day, lunch will be Human World food will be made by MC.
Everyone has assigned rooms, and MC is to share a room with Simeon and Asmodeus. Mammon demands a switch with his brother, but Asmodeus refuses, and everyone separates to put away their things. Simeon and Asmodeus have a conversation where the latter exclaims how lucky he and MC are to share a room with him, and that there can't be someone out there who doesn't love him. Satan then arrives and informs them the tour will soon begin.
When they join everyone again, Mammon accidentally reveals that he, Solomon, and Satan plan to collaborate together, as Mammon wants to steal things, Solomon wants some magical items that belong to the Demon King, and Satan "just want to give Lucifer a black eye." Of course Lucifer overhears, and tells Mammon that he expects him to come to his room later.
The tour guide is a tiny demon named Little D. No. 2, who is one of the Little D.'s that helps MC in their tasks. First on the tour is the portrait of the current Demon King, Diavolo's father. Luke comments he last saw the Demon King at a ceremony over 1,000 years ago, and Diavolo mentions he hadn't seen his father in several hundred years, as he's slumbering at the bottom of the Devildom.
While passing through the stairways, Helene, a witch trapped inside a painting, recognizes Asmodeus. Number Two explains that when Helene was in the human world, Asmodeus seduced her and she betrayed her lover at the time, leading to a war that destroyed an entire country. She uses what magic she still possesses to pull Asmodeus, Mammon, Leviathan, Beelzebub, Solomon, and MC into the painting.
MC wakes up to Solomon's calls and finds out they're alone in an underground labyrinth. Solomon summons Asmodeus using their pact, and the three of them soon find the others being chased by a giant snake that was once Leviathan's pet named Henry 1.0.
The snake pursues them, but Solomon amplifies Asmodeus's power, who then charms Henry 1.0., and he shows them to the exit. Afterwards, they explain to everyone how they escaped while eating Barbatos's delicious food.
Later that night, Mammon shows up in MC's room and wants to have a pillow fight. However, Lucifer arrives and overhears Mammon when he insults him, so he drags him away.
The second day of the retreat arrives. Mammon didn't get any sleep last night due to Lucifer, and the rest of the brothers have fun guessing what Diavolo had said. The itinerary for the day is a scavenger hunt, so each group is given riddles to solve to find a historical item in the castle and take a picture of it. However, with Asmodeus sabotaging things, Luke's group is not able to complete their riddle solving.
Asmodeus eventually leaves so that he doesn't have to hear Satan's lecturing, and MC follows. They try to make a pact with Asmodeus, but he replies that he'll agree only on the condition that they get a picture of Lucifer's sleeping face.
Later, Luke serves dishes from the Celestial Realm that he made for dinner, and MC tries to get a hint of where Lucifer's room is. After dinner, Diavolo transforms the Hall and fills it with guests from across the Devildom for the formal dance. The demon brothers and Diavolo transform into their demon forms. Mammon nervously asks MC for a dance, but then Lucifer appears and tells MC to dance with him.
As Lucifer and MC dance, he asks them what it is they are plotting. He warns MC that if they ever seem to be a threat to Diavolo or his brothers, he will show them no mercy. Solomon then appears and invites MC to dance. He comments that while MC may have pacts with demons, they don't have the power needed to command them. So, Solomon uses a spell to lend MC some of his powers for the next six hours.
Later that night, MC, Mammon, Leviathan, and Beelzebub commence 'Operation Photograph Lucifer Sleeping'. When they enter what is supposed to be Lucifer's room, they find Cerberus instead. Everyone escapes through a door, only to fall back into the underground labyrinth with Henry 1.0.
Using Solomon's borrowed powers, MC summons Asmodeus to again tame Henry 1.0. Like Solomon had before, they use a spell to enhance Asmodeus's charm. Asmodeus comments that MC is both able to draw more power out of him than Solomon ever has, and seems to have more magical power than he does.
When the four return to the castle, Lucifer explains that if someone tried to get into his room without knocking, they're transported straight to Cerberus instead. Even though MC failed to get the photo of Lucifer, Asmodeus is impressed by their magical powers and decides to make a pact with them.
Later that night in their shared room, Asmodeus is fawning over MC when Mammon suddenly appears. Satan, Leviathan, Luke, Solomon, Lucifer, and Diavolo soon show up as well. Annoyed at Asmodeus's proximity to MC, Mammon throws a pillow in Asmodeus's face, starting a pillow fight. Once the pillow fight ends and everyone goes to bed, Diavolo and Lucifer discuss MC's pact-making in the garden, while Satan is caught by Barbatos eavesdropping on the conversation.
The last day of the retreat, everyone but Lucifer and Diavolo — who are still asleep — wake up late in the afternoon, tired from staying up all night for the pillow fight. Food from the Human World is served for brunch, with dishes made by MC, Barbatos, and Solomon. Asmodeus is avoiding eating anything Solomon made, and as each of the others try Solomon's food, they understand why. Despite looking delicious, the dishes Solomon made taste terrible to everyone except Solomon himself.
Returning home to the House of Lamentation after the retreat, Asmodeus asks MC why they want to make a pact with all the demon brothers, to which MC responds that they want to earn Lucifer's respect. Lucifer asks what the point of earning his respect is, and what MC is trying to accomplish. Satan then states that he's decided he will also be making a pact with MC, which starts an argument that results in Lucifer telling Satan to get out of the house. Satan declares that he would be happy to leave, and goes to his room to pack.
Afterwards, everyone except Satan and Lucifer meet up in MC's room, where MC explains the plan to get Lucifer to make up with Belphegor. Beelzebub points out that earning Lucifer's respect won't work if Satan makes a pact with MC just to spite him. MC asks why Satan hates Lucifer, and Mammon explains that after the Great Celestial War, Satan was born from Lucifer's Wrath, and that while they all raised Satan, he was especially influenced by Lucifer.
MC then goes to Satan's room, where Satan is trying to decide which books to take with him. He warns MC of one book in particular, as it's a forbidden book that causes people to switch bodies. He then explains to MC that he is considered the "fourth-born" because the Demon King gave him and his brothers their names after arriving in the Devildom in the order of most to least powerful. While he was the last born of his siblings, he's the fourth strongest.
Satan then tells MC to make a pact with him, but MC disagrees with Satan making a pact just to irritate Lucifer, and refuses. This angers Satan, and he threatens MC, but is stopped by Lucifer. The two begin arguing, and as Satan's wrath grows, books in the room start to fly off the shelves. Lucifer grabs one of them at the same time Satan does, and in a flash of white the two switch bodies.
Satan (now in Lucifer's body) states that the effect of the body switch lasts for several days. Lucifer (now in Satan's body) still insists they go to school like this, for he does not want Diavolo asking questions. He also wants to keep an eye on Satan while he's in his body, so the two decide to stay in MC's room.
Once in MC's room, with Mammon and Asmodeus still present, Lucifer discusses how things will work. Neither he nor Satan are allowed to go into each other's rooms unless the other is present, and each will avoid doing anything that might attract attention while at school.
The next day, Lucifer, Satan, and MC run into Diavolo, who asks why Lucifer didn't visit the assembly hall first thing in the morning. Satan poorly impersonates Lucifer, but Diavolo reveals that he could tell Lucifer and Satan had switched bodies from the start. He then reminds Lucifer that he has to give a speech to the student body the day after tomorrow. Lucifer concludes that if they haven't switched back by then, Satan would have to deliver the speech as himself.
After school in MC's room, Satan — now joined by Leviathan and Beelzebub — continues to mock Lucifer with bad impressions. MC goes out into the hall to find Mammon hanging from the ceiling, and helps him down only after he agrees to help Satan and Lucifer make up.
In Leviathan's room, Mammon shows MC a game named Dogi✩Maji✩Memorium. Anyone who registers to play is actually pulled into the game world. Mammon plans to have Satan and Lucifer work together toward a common goal while playing the game. Lucifer, Mammon, Leviathan, Satan, and MC enter the game.
Once inside the game, MC and the others find themselves in a Human World school. Leviathan explains that Dogi✩Maji is a school dating sim; one character is designated the "heroine" (regardless of their gender), and the others have to increase their favorability score with them. In this case, the heroine role is played by MC. In the end, one of the players go up to the Roof of Legend and profess their love for the heroine. If the heroine accepts, they win the game.
Lucifer and Satan — now in their own bodies — challenge each other to see who will raise intimacy with MC first, and the game begins. One by one, MC interacts with each of the brothers, which affects their intimacy levels.
While MC is busy elsewhere, Lucifer, Mammon, Leviathan, and Satan hold a meeting. They discuss the fact that winning the game isn't guaranteed, so they have a brainstorming session on strategies to best raise intimacy with MC.
On the final day where the players must profess their love to the heroine, Satan apologizes to MC for getting them caught up in a weird business. If MC tells him to wait, they say that Lucifer doesn't see Satan as a child, and that he only behaves as he does because he wants to look good in front of Diavolo.
On the rooftop, instead of a love confession, monsters start appearing all over the school and the game has into an ultra-hard survival fight. Leviathan seems to be excited about the crazy plot twist in a simple dating sim. The last boss appears, and looks like Cerberus, but Satan states that it's not the real Cerberus. Cerberus charges toward Satan and is about to strike, but Lucifer commands Cerberus to sit, and warns him not to harm his brother. Cerberus obeys, and the screen states that the Mission is Complete.
Back in Leviathan's room, Satan and Lucifer again have their bodies switched in the real world. However, the two brothers seem to have an agreement begun to accept one another.
While all of this was happening, back in the House of Lamentation, Asmodeus and Beelzebub are looking for MC. As the two are cleaning up Satan's room, they touch the forbidden book and switch bodies. Beelzebub (in Asmodeus's body) comments how he doesn't feel hungry, and Asmodeus (in Beelzebub's body) states that he feels incredibly hungry and considers eating some of Satan's books.
Before he does so, both brothers suddenly return to their respective bodies. The forbidden book looks worn out, and Asmodeus states that the more it's used, the more worn out it becomes, until it eventually can't be used anymore.
While shopping in the Devildom, Lucifer — who's still in Satan's body — MC, and Mammon speak about the speech Lucifer has to make tomorrow. They then stop at Hell's Kitchen, where Lucifer treats them all to a meal, but afterwards reveals he did so that Mammon and MC are now in his debt.
Lucifer want to go to the Human World and find the witch who created the curse of the body switch in order to lift it. At first Mammon is excited about going to the human world, but then changes his mind once he heard witches are involved, because he's afraid of them.
There is an obstacle in the way of the trip, however: only certain demons can travel to the human world directly. Because Lucifer is in Satan's body, the magic circle that acts as a doorway doesn't recognize him, and so they can't travel. Satan then arrives and decides to help them, as he's in Lucifer's body, which means the magic seal lets him pass. Thus, they travel together.
In the human world, Mammon's attitude changes again and he enjoys himself. At Victoria Station, Lucifer buys four matching keychains for the entire group, which surprises Mammon, even though it was what he wanted. Once they board the train and are in a private cabin, Mammon leaves to find the dining car so he can take a picture of the food and brag to Beelzebub. However, he stumbles into the wrong room, and suddenly gets accused of a woman's murder. Lucifer, Satan, and MC arrive at the scene after hearing the woman's last scream.
The brothers and MC meet Lucas, Sophia, and Noah, who were all in the company of the dead woman, who happened to be Grisella, the witch the group was searching for. Lucifer uses his powers to hypnotize the three humans so that they leave.
Back in their own car, everyone hears the ghost of Grisella, who wants them to solve her murder in exchange for lifting the curse of the body switch. All the demons want to torture the three suspects, but MC wants to find a less violent way. They question Grisella and Mammon, and with the information Mammon gives, they guess who the killer is. As the three humans from earlier gather, the witch warns MC about Lucifer, saying he'll soon lose the trust he puts in them.
Once in front of the suspects, Satan decides to explain MC's thoughts, and then declares that the killer is Noah. He turns out to be right, as Noah says he truly wanted to become Grisella's apprentice, but the witch had refused him. She didn't want to take Noah as an apprentice because she predicted she'd die in the train, which would break the man's heart. Ironically, her refusal is exactly why she was killed.
Back in their car, Grisella keeps her word and lifts the curse of the body switch. Surprisingly, Lucifer asks Satan to still do the speech about the report he's supposed to do tomorrow, and his brother agrees with confidence.
At Ristorante Six, Lucifer proposes a toast with everyone — save Leviathan, who is absent — for lifting the curse that had he and Satan in each other's bodies. Diavolo thanks MC for how happy Lucifer is, and comments that the right choice was made having MC as an exchange student. MC asks Diavolo how they were chosen in the first place, and he explains that Lucifer chose them, while he simply gave his approval.
In a flashback, a conversation between Diavolo, Barbatos, and Lucifer takes place. Diavolo and Barbatos say they are jealous of how Lucifer enjoyed himself in the human world, then Diavolo mentions he's noticed how well MC is getting along with Lucifer and his brothers. Lucifer admits that he trusts MC now, but after he leaves, Diavolo seems worried, and Barbatos suspects that what's about to happen will wound him deeply.
As everyone is walking back to the House of Lamentation, Lucifer asks MC what they and Diavolo were talking about earlier. When they answer, Lucifer states that the reason he chose MC was due to a sudden breeze that scattered the lists, and the list them landed at his feet had MC's name on it. However, he also says that MC is special to him on a personal level. The conversation is interrupted by a call for Lucifer from Leviathan, but when Lucifer picks up, all he hears is a scream before the connection is cut off.
At the House of Lamentation, Lucifer looks for Leviathan in his room, but only finds his D.D.D. laying on the ground. Lucifer then notices that Beelzebub is also missing, so he suggests everyone split up in groups, with Satan and MC together with him. As they search, Lucifer recalls the story about the House of Lamentation. Originally, the house was built in the human world, and a married couple with seven children lived here with their servant.
One day, the oldest son ran into the constable's office with news that their servant murdered his family, then took his own life. The oldest son lived on in the house, eventually dying of old age, despite circumstantial evidence that he could have been the true killer. At some point, the house was given the name "The House of Lamentation."
Once the story is finished, Satan again asks MC to make a pact with him. MC is surprised, but Satan states that he's not asking to make Lucifer angry. He's decided that he won't let what Lucifer does bother him anymore. MC accepts, and now has their fifth pact.
Later on, the three hear screams that sound like Mammon and Asmodeus to Satan. When investigating, he suddenly disappears as well, leaving Lucifer and MC alone. Lucifer suggests they go back to Leviathan's room, and once there, they notice Leviathan's PC is still turned on. Lucifer finds the packaging for the game The Demon House with a description matching what is happening now.
Thinking the game is the cause for the disappearances, Lucifer suggests he and MC complete the game to see what happens. Upon searching for a game guide, it states that in order to complete the game, you must defeat the final boss, whose name is Lucifer. The guide also states that there is a romantic ending where the player and Lucifer fall in love.
MC and Lucifer reconvene in the library, where Lucifer states that the only choice they have is for MC to fall in love with him so they can finish the game. He suggests they start by asking each other questions. When MC asks Lucifer what he thinks of humans, Lucifer suspects the real question is what he thinks of MC. He states that originally, he'd only wanted to make sure MC survived the year, but over time his feelings changed. He asks MC why they made pacts with everyone, and MC finally tells Lucifer they met with Belphegor, which enrages him.
Mammon and the others appear, but when Beelzebub hears about Belphegor being locked in the attic, he and Lucifer argue, leading to Lucifer hurting Beelzebub. Belphegor then appears in the room with them.
Everyone is shocked and confused at Belphegor's appearance. Belphegor confronts Lucifer and things escalate, as Lucifer isn't happy about the situation, and Beelzebub is fed up. In the end, Beelzebub, Belphegor, and MC leave the House of Lamentation.
After leaving, Belphegor laughs at the memory of the look on Lucifer's face, but then asks Beelzebub if it was really okay to leave like that. He answers that he doesn't know, but that they can't go back anymore. He then apologizes for taking MC with them, explaining that he thought it would be dangerous to leave them with Lucifer.
Beelzebub tells MC that the brothers had all gone missing earlier as a practical joke in order to bring Lucifer and MC closer. He then says that sitting and hiding so long has made him hungry, which makes Belphegor nostalgic. Belphegor then comments that he can smell something good, and Beelzebub recognizes the scent of Simeon's BLT devil sandwiches. Sure enough, Simeon shows up, and is surprised at seeing Belphegor. When Belphegor asks him if they can stay at Purgatory Hall, Simeon agrees, but feels like something is going on.
In Purgatory Hall, Beelzebub explains to Simeon, Solomon, and Luke about what's been going on with Belphegor. Solomon and Simeon express disbelief in the entire situation. Belphegor goes on to explain the curse that kept him locked in the attic, which required the power of six of his brothers to break. That why he asked MC to make pacts with everyone.
However, MC explains that they hadn't made a pact with Lucifer, leading everyone to question how the curse was broken. Belphegor claims that he heard a voice, then he found the door was open. Solomon then points out that even if MC had made a pact with Lucifer, it still wouldn't have been enough, as they lack the ability to control the brothers' powers. Simeon then suggests that someone else must have taken Lucifer's place and filled in as the sixth sibling.
Later on, after bribing Luke to let MC, Beelzebub, and Belphegor use his room to sleep in, Belphegor is still relishing in his freedom. Beelzebub tried to press Belphegor for why he was locked in the attic, but Diavolo suddenly appears, and interjects that if Lucifer hadn't locked his brother up, Belphegor might have destroyed the human world.
Both Diavolo and Barbatos enter the room, and explain that Belphegor vigorously opposed the exchange program. He'd attempted to appeal to Lucifer, but Lucifer had supported the program. Diavolo further explains that Belphegor hated humanity and couldn't accept Diavolo's plan for uniting the Devildom, Celestial Realm, and the human world. Belphegor was angry, to the point that he was a threat to the human world, which prompted Lucifer to lock him in the attic for his own protection.
Belphegor becomes angry when Diavolo claims Lucifer was sheltering him, declaring that he was a prisoner in the attic. Diavolo then corrects him, saying Lucifer was indeed protecting Belphegor from him, then has Belphegor arrested for treason. Beelzebub attempts to interfere, but MC stops him. Diavolo warns them both that if they choose to defy him, things will only get worse for Belphegor. He then explains Belphegor will face justice for his actions, and that Lucifer has been placed under house arrest in the House of Lamentation. He then tells MC to stay out of this, claiming it's a demon matter, and as a human exchange student, they have no involvement. Both he and Barbatos then leave, taking Belphegor away.
MC and Beelzebub return to the House of Lamentation with intentions to talk to Lucifer about Belphegor. First, however, goes to Mammon to apologize and ask him for help. Mammon tells MC that Lucifer had locked himself in his room, and to get him out they're going to need as much help as they can get. So, they both go to find Leviathan.
They find Leviathan talking with Henry about how betraying and awful humans are, ignoring MC's and Mammon's presence in his room. Mammon tries to explain that MC's pact with him didn't have anything to do with Belphegor, but Leviathan doesn't believe him. MC makes a TSL reference regarding the friendship between the Lord of Shadow and Henry, leading Leviathan to hug them and call them his true friend.
The trio is then joined by Satan, Asmodeus and Beelzebub, and they all gather in the underground tomb to follow Mammon's plan. He wants MC to touch the grimoire so that Lucifer will leave his room. However, they first need to sneak past Cerberus, who is patrolling the area.
When MC touches the grimoire, they see a flashback of when Lucifer fell into the Devildom with a dying Lilith after the Great Celestial War. Diavolo appears before him, and at Lucifer's request, promises to save Lilith. However, in return for the great risk of interfering with the Celestial Realm's judgment, Lucifer would have to pledge his loyalty to Diavolo. To this, Lucifer agrees.
When the flashback ends, MC tries to pick up the grimoire, but can't because of the ivy covering it. As Cerberus approaches, Lucifer appears and commands him to sit. MC can either hug or hit Lucifer, and both responses surprise him.
MC gathers everyone back into the mansion to talk about Belphegor. Lucifer reveals that he had locked Belphegor away for his own protection, because he was openly against the human race and put Diavolo's exchange program in jeopardy. Belphegor's reason for hating humans stems back to Lilith's death, as he believes that humanity was responsible.
Meanwhile, back in the Purgatory Hall, Luke is worried about MC and Beelzebub, while Simeon and Solomon try to calm him down. Solomon wonders why Lucifer is loyal to Diavolo, and Simeon comments that Diavolo and Lucifer seem like close friends rater than master and servant, or at least Diavolo sees Lucifer like that.
In a flashback of Simeon visiting the Devildom for the first time after Lucifer's rebellion, he finds Diavolo being extremely friendly with Lucifer, to the point Lucifer had to stop him from embarrassing him any further. Solomon's and Simeon's conversation is interrupted by Luke yelling about his burnt cookies.
In one last flashback, Belphegor is talking to himself in the attic when Lucifer appears. He asks if Belphegor has calmed down yet, reminding him that he was meant to use the time in the attic to rethink what he'd said earlier. Belphegor responds that he'll be stuck here forever, because he'll never change his mind.
Lucifer tells him they're chosen the second student from the human word, and that they are an average, non-magical human. Belphegor threatens to tear them to shreds, ruining both the exchange program and Diavolo's reputation. Lucifer tells him that won't happen, because the door to the room can only be seen by demons, and the stairs are cursed so that no demon but Lucifer can climb them.
After Lucifer's explanation as to why Belphegor was locked in the attic, MC asks why he hates humanity in the first place. The brothers explain that, as an angel, Belphegor loved humans and often visited the Human World in secret. His visits led to their sister and youngest sibling — Lilith — also being interested in humanity, and eventually to her falling in love with a human. Unfortunately, the man was stricken with an incurable illness, and in an attempt to save him, Lilith gave him forbidden food from the Celestial Realm.
Because altering the lifespan of a human is forbidden, when caught, she was sentenced to be wiped from existence, which of course Lucifer and his brothers refused to accept. Their rebellion turned into what was afterwards called the Great Celestial War. It was a war the brothers lost, and fell into Devildom, becoming demons.
Belphegor blamed the man Lilith had fallen in love with, and argued that she wouldn't have died if neither he nor humanity as whole had never existed, so he began hating humans. However, Lucifer also reveals that Lilith did not die at the end of the war, but was instead saved by Diavolo and reborn as a human, which is why Lucifer swore his loyalty to him.
After hearing all of this, MC and the brothers decide to pay Lord Diavolo a visit. They ask Diavolo to release Belphegor, to which Diavolo eventually agrees, but only under the condition that MC travels back into the past and ascertain exactly who it was that freed him from the attic.
With the help of Barbatos, MC returns to the time when the brothers were pretending to disappear. After being spotted by them, they explain that their plan was to get Lucifer and MC alone together to make up. The brothers urge MC to go back to Lucifer and patch things up, so MC leaves. They arrive outside Leviathan's room to hear Lucifer complaining about how ridiculous the game is, then nearly run into both him and their past self.
To avoid being seen by their past self, MC hides in the hidden replica of Lilith's bedroom. They start seeing disconnected events of the past, including an argument between Lucifer and Belphegor about the exchange program. MC heads to the attic to find the door to Belphegor's room missing, but after touching the wall where it should be, the door magically opens.
They enter the room, and Belphegor overwhelms MC with his appreciation upon realizing that he is free. However, suddenly he turns into his demon form, and mocks MC for falling into his trap. He then attacks them, intent on ending the exchange program by killing MC.
MC faints from the pain, and they hear the voice of Lilith in a dream-like world. Lilith explains she no longer has a physical form, but after her death as a human, she recalled her memories of her past life. Since then, she'd been watching over her brothers as a soul. Lilith then lends MC her powers so that they can save her brothers.
In the timeline MC left, the brothers anxiously await MC's return, minus Lucifer and Beelzebub, who visit an imprisoned Belphegor only to find him sleeping. Lucifer apologizes to Beelzebub for lying to him about Belphegor being in the Human World, and Beelzebub tells Lucifer he can make up for it by trusting his brothers more.
Back in the past, MC wakes up completely unharmed. They hear an argument downstairs, and head to the source to find a duplicate of themself dying in Mammon's arms. The brothers are panicking, horrified at the idea of MC dying, when they spot the future MC standing there. After a moment of confusion, the MC in Mammon's arms disappears. Belphegor begins to attack MC again, but stops when MC tells him about what really happened with Lilith.
Lucifer asks where MC heard that story from, and Diavolo enters the scene to reveal that MC is a distant descendant of Lilith's. He asks MC if they ever had visions of Lilith's memories, and MC recalls the memory of Lucifer pledging his loyalty to Diavolo. Diavolo then postulates that some of Lilith's angelic powers and memories remained even after being reborn a human, and both had passed on through her descendants.
The brothers are overjoyed both that MC is alive and well, and to learn that their sister lived a happy life that resulted in MC being here with them now. Belphegor apologizes, and finally admits the truth; he blamed himself for Lilith's death, but tried to escape his feelings of guilt by blaming humanity instead. Lucifer responds that Lilith's death wasn't his fault, and that he should've told him that sooner.
Some time afterwards, the brothers — including Belphegor — are fawning over MC. MC asks Barbatos about their disappearing double, and he tells them another power of his: he can choose from any number of potential realities and make his choice the sole reality. Because the reality he chose was one where MC was never harmed, the other MC disappeared, having no longer ever existed.
In a flashback, Lucifer is buried in paperwork for choosing the second human exchange student. Diavolo suggests choosing a human completely different from Solomon, but when Lucifer decides to take a break and open a window, a gust of wind sends the paperwork flying everywhere. The paper that landed at his feet has MC's name on it, and Lucifer decides they will be the second human student. Diavolo states that nothing is a coincidence in this world, and agrees with Lucifer's decision.
The brothers are having breakfast as usual, but when Belphegor enters, things get awkward. Leviathan announces that he's going to grab his food in the cafeteria. Beelzebub, Satan, Mammon and Asmodeus come along. Asmodeus questions MC whether they are coming along too, to which they can either agree, or say that they'll wait for Belphegor. Lucifer then enters to announce Diavolo's birthday party, and everyone heads to RAD.
Belphegor notices his brothers' wariness of him, as does MC, so Simeon suggests MC "serve as a bridge" for the brothers. After school, MC goes to the planetarium with Belphegor, and asks them what they were planning on giving Diavolo for his birthday, but they're interrupted by a loud noise coming from the music room.
They catch Mammon rummaging through the room, and Belphegor accuses him of stealing. Mammon retorts that he wants to give someone a present. Belphegor asks if the present is for Diavolo's birthday, and Mammon seems to suddenly remember that's coming up soon, but agrees that the present is for Diavolo. Belphegor changes the topic to getting money for Diavolo's present. He suggests working in Hell's Kitchen, which the three decide to do.
Afterwards, Leviathan meets up with MC, and says that Belphegor wants to play games with him. He worries that it would be awkward, so he tells MC to give Belphegor the message that he's busy waiting to accept a package from Akuzon. MC leaves for the twins' room and gives the message, but Leviathan shows up to say the package had been delivered, so he brought some games with him for all three of them to play. Belphegor falls asleep in the middle of gaming, to which Leviathan seems surprised and slightly disappointed, but then comments that he shouldn't have worried about things being awkward.
Later, MC and Belphegor are playing card games, with Belphegor repeatedly losing. Lucifer then enters, and wants to talk with Satan about Diavolo's birthday. Satan agrees, and the two leave. Belphegor notes that Satan was acting strangely agreeable with Lucifer, and asks MC if they know anything. MC tells him about the forbidden book incident, and how Satan and Lucifer's relationship changed.
After the story, Belphegor says wishes he'd been there. Satan returns and overhears them, then comments on how he still loves to see Lucifer suffer. Belphegor then suggests forming "The Formerly Anti-Lucifer League" with the goal to make Lucifer's life as hard as possible. The three adjourn to the library to discuss the group's first prank: putting hot sauce in Lucifer's prized vintage Demonus.
Said Demonus is kept in Lucifer's study, which is behind a secret door in the library. They assume a secret code or phrase is needed to lift the enchantment and open the door, so start trying taunting phrases to get the door open. Unfortunately, they are caught by Lucifer, who tells them to come with him for a stern talking-to.
MC and Belphegor are out shopping for Diavolo's birthday present, when Solomon appears, and tells Belphegor he'd like a pact with him, He notices that Belphegor glances in MC's direction, then declines his offer of a pact. He and MC then head back to the House of Lamentation, where Asmodeus comes along and drags them both to his room. He asks MC what sort of outfit they like, then reveals that the outfit is for MC, but Belphegor then pulls MC out of the room.
Later, MC, Leviathan, and Mammon are playing a video game in MC's room, but Belphegor interrupts them after a fight with Beelzebub. He tells them that it was because Beelzebub was feeling guilty due to not knowing Belphegor was being held prisoner. Belphegor asks MC if he can sleep in their room, but Mammon aggressively declines, and offers to help Belphegor and Beelzebub to make up.
When MC and Mammon search for Beelzebub, they find him in the kitchen cooking soup for Belphegor. The three take the soup back toward MC's room, and Beelzebub worries whether or not Belphegor would forgive him. Leviathan and Belphegor come out of MC's room, and Belphegor, tired of Beelzebub's behavior, slaps him, and says firmly that what happened wasn't Beelzebub's fault. The two are then able to make up.
After a day of school, Lucifer invites MC to go shopping with him for Diavolo's present, and then the two have dinner at Ristorante Six. Lucifer raises the topic of MC helping Belphegor and his brothers patch things up, and thanks MC for helping them. Then then return to the House of Lamentation to find Belphegor, and Lucifer invites him as well as MC to come with him and provide an opinion.
He leads them to Lilith's room from the Celestial Realm, and confesses that he created the room to never forget Lilith, but the secret of Lilith's reincarnation had been too much too bear, so he'd unloaded it all here. He says that he doesn't need the room anymore, but wants Belphegor to use it if he needs it. Belphegor says that he also doesn't need the room, but thanks Lucifer for being able to make the decision, and the two make up.
At the Demon Lord's Castle begins, Diavolo's party begins, but he reveals in a speech that the party is meant for MC too. The brothers all give MC their gifts, but Belphegor is nowhere to be seen. MC finds him in the garden, where admits he wasn't sure what to give MC, so he decided to give himself. He makes a pact with MC, and then Asmodeus, Beelzebub, and Mammon find them, and urge them to go back to the party.
In a flashback before the party, the brothers are in Lucifer's private study, where he announces his idea of making Diavolo's birthday party also be a welcome party for MC. Asmodeus decides to buy a present for MC, so the others decide to do the same. Belphegor raises the idea that he should give MC himself by making a pact with them. The other brothers each try to subtly ask MC what they would want as a gift.
After the birthday/welcome party is over, Beelzebub and Satan are playing chess in the music room with MC and Belphegor. Lucifer then enters, and tells Belphegor that he has to make up for all his missed classes. He gives Belphegor all of his assignments, and tells Beelzebub and Satan not to help him.
Later, Belphegor is studying in the twins' room with MC helping, when one by one Mammon, Asmodeus, Satan, Beelzebub, and Leviathan each enter the room. They all try to help Belphegor in their own ways, but are mostly just distracting. Belphegor finally snaps, and takes MC with him to his attic room. He thought he could now focus on his schoolwork, but instead falls asleep on MC's shoulder.
The brothers are once again having breakfast, and as Beelzebub eats Leviathan's meal again, everything in the Devildom seems back to normal. Belphegor enters as the room, and Mammon comments that he woke up even later than Leviathan. Lucifer then also enters the room, and asks MC to join him tomorrow for a meeting with Diavolo discussing the end of their stay as an exchange student. The room is filled with silence, as all of the brothers are upset.
Breakfast ends, and everyone is getting ready to head to RAD. Lucifer requests MC stay behind, and tells them his brothers are sad that MC's leaving, so he wants MC to spend as much time with them as they can. Once classes are over, Mammon invites MC to hang out, but Leviathan interrupts, demanding Mammon give his money back. Mammon makes a break for it with MC, but Leviathan is close behind.
Still being chased, MC can either suggest hiding in Mammon's room or Leviathan's room. If MC suggests Mammon's room, they'll hide in the trunk of his car. If MC chooses Leviathan's room, they hide in Leviathan's bathtub he uses as a bed. Leviathan enters, then tells Henry that he's sad MC is leaving next week. He eventually leaves the room, and MC and Mammon leave as well.
The two make it out of the House of Lamentation and get some distance between themselves and Leviathan. Mammon laughs about the look Leviathan had on his face as they escaped, then questions MC about staying in the Devildom. However, Leviathan has caught up to them, so Mammon runs away. Leviathan, tired of chasing him, and admits that he too, wants MC to stay in the Devildom.
The next day, the scheduled meeting takes place in the Student Council Room. Diavolo states that Lucifer seemed distraught over MC going back to the Human World, and that he's also sad about MC leaving. Once school is over, MC is spotted by Asmodeus, who invites them to hang out. The two go to Hell's Kitchen, where Asmodeus challenges MC to a drinking contest.
The contest involves drinking Demonus — a common alcoholic Devildom beverage — which turns out to have no intoxicating effect on humans. Because of this, MC wins the drinking contest, which leads to a drunk Asmodeus hugging MC with tears in his eyes as he asks them to stay in the Devildom. Satan finds them like this, and carries Asmodeus back to the House of Lamentation.
He puts Asmodeus to bed and returns to his room, where MC was waiting. He has something to ask MC, and starts talking about a book of old folktales he recently acquired from the human world. In one story, a king is given aid in winning a war by a beast with magical powers. The king then kills the beast, who turns into a monster and curses the entire country. To end the curse, the king offers his newborn daughter as sacrifice. Twenty years later, the daughter is seen still alive, and people try to kill her out of fear. The monster appears and saves her, giving up his own life.
Satan asks what MC thinks the beast felt in its dying moments, and then wonders in confusion what it is he's feeling for MC now. He says that he knows MC returning to the Human World doesn't mean they'll never meet again, but the thought of them not being around still makes him sad.
MC is at RAD chatting with Simeon, Luke, and Solomon about leaving the Devildom. Solomon suggests they should all meet up again someday, and everyone agrees. After school at the House of Lamentation, MC finds Beelzebub searching for Belphegor, and helps look for him.
Eventually, MC and Beelzebub find Belphegor sleeping in the attic room. Beelzebub is relieved to find him, then thanks MC for bringing their family together. Belphegor then wakes up, and Beelzebub admits to Belphegor his worries about him running away. Belphegor tells him not to worry, and Beelzebub heads for the kitchen.
After Beelzebub's gone, Belphegor suggests that he, Beelzebub, and MC live together, but then admits what he's asking is selfish, because MC has a life in the human world to return to. Beelzebub then returns with a mountain of snacks, followed by Mammon, Leviathan, Asmodeus and Satan. A going-away party begins, but after awhile MC leave to find the door to Lucifer's secret study is open, and music plays within.
MC goes inside to find Lucifer listening to the cursed vinyl edition of The Tale of the Seven Lords soundtrack. Lucifer notes that he chose MC as the exchange student in this room, and that while there were times he thought he'd made a mistake, he's now certain he made the right choice. He asks MC if they finished everything they set out to do in the Devildom, and MC answers that they haven't made a pact with him yet. Lucifer then turns into his demon form to intimidate MC, and asks if they still want a pact with him. Regardless of MC's answer, Lucifer still makes the pact.
On the final day, Diavolo, Barbatos, the seven brothers, and the exchange students are is gathered in the Student Council Room, where said exchange students will be sent back to their own worlds. Simeon, Luke, and Solomon leave first, after saying their goodbyes. Diavolo gives his farewell to MC, followed by each of the brothers, before MC returns to the Human World. MC then gets a message from Solomon informing them they can still use their D.D.D. in the human world.
Some time later, Barbatos serves Diavolo tea that he procured from the human world, which makes Diavolo think of MC. Barbatos notes that it has been quite a while since MC left, yet everyone is still in low spirits. He questions whether Diavolo is unhappy. Diavolo admits he might be, then asks Barbatos if he's sad his baking partner Luke is gone. Barbatos answers that he is.
At the House of Lamentation, Leviathan and Mammon are arguing over money Mammon owes, to which Lucifer threatens Mammon with hanging him upside down. Satan complains that he was hoping for someplace quiet to read his book, then Asmodeus starts complaining that Beelzebub ate his special sweet he wanted to post about on Devilgram. He wishes MC were there, and Leviathan agrees that they'd find a way to fix everyone's conflicts.
Belphegor then enters, and comments that the room feels somber before asking if anyone had seen his D.D.D. He says today is the day MC calls him, which fills the others with shock and jealousy. Everyone then hears Belphegor's D.D.D. ringing.
In the Devildom, Solomon tells MC to take a dagger and thrust it into someone's chest, but MC's vision suddenly goes black. They regain awareness back in the Human World to the sound of their D.D.D. ringing. The call is from Mammon, who asks how MC is doing, then complains that Lucifer insisted the brothers take turns calling MC.
He has to hang up shortly after, as Satan is calling him to go to a Student Council meeting. Afterwards, MC gets a text from Solomon, but in the middle of the text conversation, he shows up in person. He tells MC that they need to "get going" and uses his magic to teleport them both to the Devildom.
In the student council room at RAD, a meeting is being held. However, all of the brothers — minus Lucifer — are instead talking about whose turn it is to call MC next. Suddenly, Solomon and MC appear. Everyone is surprised, including Diavolo and Barbatos. Belphegor asks MC if they're staying for a while, but says that their room at the House of Lamentation is covered in dust, so Beelzebub suggests that MC stay in the twins' room instead.
An argument breaks out over where MC will stay, but Diavolo interrupts. He tells MC he's happy to see them, but that they were in the middle of an important meeting. Lucifer gives MC a key to the house, and tells them to wait there.
Solomon escorts MC to the House of Lamentation, then heads for Purgatory Hall. The brothers return home shortly after, and Lucifer complains about everyone losing their composure as soon as MC showed up. The others point out that Lucifer wasn't any different, which is why Diavolo ended the meeting early.
At dinner, Leviathan comments that the soup Mammon made tastes strange. The others agree with him, including Mammon himself. Leviathan then changes the subject, because he wants to show MC the bottle of Gold Hellfire Newt Syrup he recently bought. However, the bottle is empty, and Mammon admits it's because it was the secret ingredient he used in the soup.
Leviathan is furious, and says that syrup was an expensive item modeled after a remedy within the The Tale of the Seven Lords universe. Satan asks Leviathan what the syrup's effects are, and his face suddenly turns red. He then tells MC to stay away from his room, then runs away.
MC and Satan meet up in the library, where both were looking for more information on what the syrup does. Satan says he knows a book that probably has the information, but can't find it in the library, so the two go to his room to look there. They eventually find the book, which says that when consumed by demons, Gold Hellfire Newt Syrup is a potent aphrodisiac, though this heightened sexual desire is felt towards humans only. It's possible to neutralize the effects if the demon carries out an order issued by a human they have a pact with.
After reading the book, MC gives Satan an order to either hug them, kiss them, or meow like a cat for them. Satan obeys, and the effects of the syrup wear off. He then warns MC that the syrup is very powerful, and that they should make sure none of his brothers find them.
MC leaves Satan's room and runs into Beelzebub, who seems to be acting normal. He asks MC if they want to come with him to the kitchen. Once there, however, the syrup starts to take an effect, and he asks MC if he can nibble on them. MC grabs a cream puff for him instead, but said cream puff belongs to Belphegor, who cursed it so that it explodes when picked up.
Whip cream covers MC, who can order Beelzebub to clean it off their lips, their hand, or to grab them a towel. Beelzebub obeys the order, and the syrup's effects disappear. Belphegor then enters the room, angry that his cream puff was touched.
In a flashback before the meeting began, Simeon texts Lucifer from the Celestial Realm to ask him how things have been, to which Lucifer answers they are "the same as ever." Luke enters the room looking depressed, and Simeon asks if it's because Luke misses the Devildom. Luke dismisses the idea, then Simeon gets a text from Solomon telling him that he's in the Devildom with MC.
An angry Belphegor storms off, and Beelzebub urges MC to chase after him. MC finds Belphegor on the stairs to the attic, and he admits he can't be around them because the Gold Hellfire Newt Syrup has started to take effect. He goes up to the attic, and MC follows. Belphegor says that if MC wants to be forgiven, they have to do whatever he wants, so MC gives Belphegor a massage. MC suddenly starts tickling Belphegor, who tickles MC back. When MC tells him to stop, it counts as an order and the syrup's effects fade.
Back out of the attic, MC encounters Asmodeus in the hallway, and he accidentally pushes MC to the ground. MC tells Asmodeus to get off them, which he does, but then he starts wheezing. MC helps Asmodeus to his room, where he says that he's going to die from the tightening in his chest, so he gives MC a last request: to put their arms around him. When they do, he gives up the act, and tells MC that the effects of syrup were already cancelled when MC ordered him to get of them.
Lucifer then enters the room, and gives MC a package that was addressed to Leviathan, but was sent to his room instead. Asmodeus ask Lucifer how he isn't affected by the syrup, and Lucifer answers that something like that would not affect him. MC leaves and knocks at Leviathan's door. Leviathan asks for the secret phase, which begins with "The second lord..."
MC then enters, but Leviathan asks them to not come any nearer. However, he can't keep himself from throwing his arms around MC and admitting that he missed them every day. He asks MC to give him an order, which they do. Mammon then starts texting MC a bunch of emoji spam.
MC goes to see Mammon, who's angry at MC for going to his brothers first instead of him. He admits that he has been thinking of MC as much as he's been thinking of schemes to make money. MC can order Mammon to kiss them, hug them, or shake like a dog, to cancel the effects of the syrup. Diavolo then texts MC to tell them that he's arranged for their stay in the Devildom.
Lucifer also texts MC, asking them to come the library and sign some papers for their stay in the Devildom. Once finished, he asks MC to give him the papers, but blushes when their hands touch. He finally admits that he's been hiding how much the syrup is affecting him, and asks MC to give him an order. MC can order Lucifer to kiss them, hug them, or tell him to stay. Lucifer obeys the order and is cured, but they suddenly hear screams. Asmodeus enters the room, and says Leviathan had another bottle of the Gold Hellfire Newt Syrup that Mammon tried to steal, which led to a fight, and now both of them are covered with the syrup.
In the Celestial Realm, Luke is still behaving depressed and denying it. Simeon asks if he wants to see MC and Solomon, then suggests inviting them both to visit the Celestial Realm. Luke races off to ask Michael about it, and Simeon texts Solomon to ask him why he suddenly brought MC to the Devildom. His answers are evasive, so next Simeon texts Lucifer about it. However, at the time of his texting, Lucifer is still under the influence of the Gold Hellfire Newt Syrup, so he can't focus only anything other than wanting to see MC.
Luke and Simeon text MC to invite them and Solomon to the Celestial Realm. MC asks Diavolo at RAD about it, and he explains that MC being a short-term exchange student in the Devildom doesn't prevent them from visiting the Celestial Realm. When news reaches the brothers — minus Lucifer — at the House of Lamentation, everyone wants to go with MC. Mammon suggests MC draw a card, and the number they pick will represent who gets to go with them.
MC picks Mammon's number, but it's discovered that all of the cards are identical. Lucifer enters, and tells his brothers to forget about going to the Celestial Realm. Solomon then texts MC to tell them he's heading to the Demon Lord's Castle, and will see MC there. Everyone bids MC farewell, and Lucifer escorts them out.
Once at the castle, Lucifer bids MC goodbye, and both they and Solomon follow Barbatos to the garden, where the gates of the Celestial Realm open for them. After the two arrive, Solomon mentions that it's his second time visiting the Celestial Realm. A voice calls out to them, and both Luke and Simeon arrive.
Luke tells MC that Michael wanted to meet them, but Simeon explains it wasn't possible due to a sacred spring starting to dry out. Solomon mentions that both Luke and Simeon will be coming back to the Devildom with MC and him as part of a short-term program. Both MC and Luke had no idea, and Luke is upset that Simeon didn't tell him. The four of them all return to the Devildom.
Once again at RAD, Lucifer announces that there will be a student council meeting, and that MC needs to be there as well. The meeting is about the upcoming school festival, and Diavolo selects MC to head the committee. The first task is to decide what will they do for the event, wants MC to have suggestions ready for the next meeting. Diavolo tells Lucifer he notices they're one officer short before departing.
The missing member is Belphegor, and a furious Lucifer orders everyone to find him. Lucifer has too much work to do for searching, and so does Leviathan, Mammon and Satan. Asmodeus, Beelzebub, and MC search for Belphegor, but he's nowhere to be found. The search continues at the House of Lamentation, where Asmodeus splits off, but Beelzebub and MC stick together. After searching several places and not finding him, Beelzebub searches his and Belphegor's room and suggests MC search somewhere else.
MC enters the attic and finds Belphegor just waking up. He jokes that if he knew it was them, he would've kept sleeping so that MC would kiss them awake. Beelzebub and Asmodeus then enter the room, and Asmodeus reminds Belphegor that he missed the student council meeting. They all go downstairs, but instead of reaching the library like they should have, they're in the music room. Belphegor notes that he doesn't have any signal on his D.D.D., and everyone wonders what is going on.
After trying to go through many doors in the House of Lamentation, it's discovered by MC, Asmodeus, Beelzebub, and Belphegor that none of the doors lead outside. They wind up in the kitchen, where Beelzebub's finds a cake that looks like an anime character Leviathan likes. Just as he's about to eat it, Leviathan appears to protect it. Thankfully, the next door opens to outside the house. Levi informs the rest that he forgot to turn off his new 3D escape game, which was the cause for the door phenomenon.
Some time later, Belphegor finds MC in their room and shows them the pile of work Lucifer gave him as punishment for missing the meeting. He tells MC he's getting hungry — due to not being allowed to have dinner — and asks if MC would come with him to get a snack. They find the kitchen door locked by a spell, so they head for the Planetarium instead.
Belphegor asks MC if they are okay with Diavolo assigning them to lead the festival committee, then says he thinks that Lord Diavolo is self-centered. Eventually, Belphegor and MC both fall asleep, and Lucifer punishes Belphegor the next morning by not letting him eat breakfast because he didn't complete his assignments.
MC and Belphegor are still together at RAD when Diavolo walks in to tell MC he wants them at the student council meeting later. Belphegor tells Diavolo it's annoying how he makes decisions on a whim, to which Diavolo says he understands how Belphegor feels, then hands him an energy drink made by Barbatos.
MC follows Diavolo out to find him puzzled about the door leading to the wrong location. MC explains that they'd borrowed Leviathan's game, and that it must have activated when they dropped it. Diavolo thinks it sounds fun, so they work together to try and get to the student council room.
Along the way, MC asks Diavolo about Belphegor's comments, and Diavolo says he will take what Belphegor said into consideration. The next door they open leads to the colosseum, and Diavolo tells MC the colosseum was here before RAD, but was once destroyed in a war with the Celestial Realm. It's also where he found Lucifer holding Lilith in his arms. He looks sad, and wonders if choices he made to reach this point where the right ones, but then asks MC to ignore what he just said.
The next door finally opens to the student council room, where Mammon and Satan are complaining about how long it took to get there. The meeting about the festival starts now that Diavolo and MC are here, and Diavolo asks MC if they have any suggestions for what the student council should do. Eventually, the group settles on doing a play. After the meeting, Lucifer takes Mammon, Leviathan, Beelzebub, and MC aside to ask who is responsible for the door phenomenon. When he learns the game Leviathan bought is at fault, he gives him a lecture.
Back at the House of Lamentation, everyone is discussing the plot of the play when Satan suggests they ask for Simeon's help. Leviathan asks why, and Satan tells him that Simeon is the author of The Tale of the Seven Lords, rendering Leviathan speechless.
The brothers and MC have a brainstorming session to decide what the play will be about, and MC suggests a fairy tale. Satan and MC then find Simeon and ask him to write the script for them. Simeon agrees, but when starting to work on it after school at Purgatory Hall, he encounters a shocked Luke, who also had no idea that he wrote TSL.
Satan, Luke, Simeon, and MC are at RAD discussing plot ideas for the play. Simeon asks Satan and MC if they have a rough idea of a theme for the play, to which Satan responds, "Prince Lucifer and Princess Diavolo." Simeon exclaims that he loves the idea, and is 100% in on coming up with a story on that basis.
The group builds on this idea, and Simeon asks MC what type of demon the protagonist is, what kind of story the play will be, and how the play should end. The choices MC makes do affect the play in future lessons. The meeting is dismissed, and the next step is to get Diavolo's approval. They find him in the student council room, and he loves the idea. Simeon states that they should go to Leviathan next for costumes.
At the House of Lamentation, Simeon and MC knock on Leviathan's door. He asks a TSL question as a test to get into his room, but is shocked to realize Simeon is there too. The pair enter Leviathan's room to find him standing with his eyes closed because he doesn't think he's worthy to be in the same room as Christopher Peugeot, which he now knows is Simeon's pen name. Simeon asks Leviathan if he would make the costumes for the play, and Leviathan accepts.
At dinner, Lucifer tells Leviathan, Asmodeus to go out and buy the needed materials for the costumes, with Beelzebub and Mammon accompanying them. During the trip, Leviathan, Asmodeus, and Beelzebub end up going off in their own ways, leaving only MC and Mammon together. Suddenly, Little D. No. 2 runs up to Mammon while calling him "Papa." Mammon insists he stop calling him that, and asks what he's doing there.
No.2 explains that he, Diavolo, and Lucifer are investigating an illegal casino — which Mammon pretends not to know about — but he got separated. No.2 asks Mammon and MC to help him find Diavolo and Lucifer, then tells them he last saw Diavolo at the traveling carnival nearby.
At the Devil's Coast carnival, a wandering ghost snaps a pic of Mammon and MC and tries to get them to buy the photo. MC can offer to buy the photograph, or No.2 will buy it for them. The group then play a crane game filled with zombie iguana stuffed animals, and Mammon wins one for both No.2 and MC. After MC bumps into Mammon while they're walking through the crowded carnival, he tells them to hold his hand.
No.2 says he is jealous, then complains that Barbatos is a tough boss, and that Lord Diavolo is the only one who shows the Little D.'s kindness. Mammon points out that they still haven't found Diavolo and Lucifer, so No.2 takes them where he thinks the casino might be: a haunted house attraction.
Little D. No. 2 scares Mammon, and as he tries to let go of MC's hand, he realizes a curse has stuck their hands together. The group head deeper inside the building, where Mammon and MC get separated from No.2 and end up locked inside a room. An unknown voice asks the two questions about each other, and if they get them right, they can escape. If not, the will be eaten by zombies. The questions are about previous lessons, but even if the questions are answered correctly, the zombies are still set loose. Mammon and MC manage to escape, and find No.2 waiting for them.
Little D. No. 2 tries to get Mammon and MC to ride the roller coaster with him by claiming it must be the location of the illegal casino, but Mammon calls No.2 out for leading them on a wild goose chase. He suggests they ride the Ferris wheel, and when No.2 complains, tells him not to come with them. Once on the Ferris wheel, MC receives a text in the "House of Lamentation (New)(8)" group chat from Asmodeus, who wants to know where MC and Mammon are. MC replies they're at a carnival, to which the brothers say they're coming to find them.
MC and Mammon meet back up with No.2, and then Lucifer shows up with Diavolo. Seeing that Mammon and MC are holding hands, Lucifer notes that the zombie iguana MC is carrying is cursed. Lucifer demonstrates by asking for the plushie and touching Diavolo, who he becomes stuck to. He lifts the curse, then confronts Mammon about the illegal casino. Diavolo steps in to interrogate Mammon, dragging him away along with No.2.
Lucifer requests MC ride the Ferris wheel with him. While on the ride, he brings up how MC and Diavolo showed up at the meeting together that day. He states that since then, Diavolo hasn't seemed like himself, and MC convinces him that he should ask Diavolo directly. Afterward, Lucifer suggests looking for him and Mammon. If MC takes his offered hand, he speaks about a memory of holding Lilith's hand long ago.
They find Diavolo, No.2, and Mammon at a restaurant, where one of the ghost servers delivers a Babel parfait "the size of a mountain." Diavolo informs everyone that if the four of them eat it within an hour, they'll get it for free. Barely a third through the parfait, Beelzebub and Asmodeus arrive, and as Diavolo is explaining their hour is up, Beelzebub finishes the parfait.
Asmodeus informs Lucifer that all of their shopping is completed, and that Leviathan returned home to get started on the costumes. Diavolo and No.2 excuse themselves, paying the tab on the way out. Asmodeus complains that Lucifer and Mammon got to have fun while everyone else worked, and suggests doing something fun together. Beelzebub stays behind to take the Babel parfait challenge himself.
After riding a thrill ride called the heaven's wheel, Satan and Belphegor show up, who Asmodeus had invited. Satan wonders where Beelzebub is, then the group hears him throwing a hunger tantrum. Everyone heads back to the restaurant to find Beelzebub demanding another parfait after finishing the previous one in 15 minutes. When the ghost waiter declines, stating the restaurant will go bankrupt, Beelzebub transforms into his demon form.
Chaos breaks out as the ghost staff throws plates to fight back. Satan gets hit in the face by a plate of pancakes, and transforms into his own demon form in rage. Lucifer tells Satan to calm down, but this only makes him angrier. Asmodeus mistakes another plate thrown by a ghost as being thrown by Mammon, and hits Belphegor in the face with a cookie when trying to hit him. MC realizes they must do something, and invokes all six of their pacts at once, pinning the brothers in place.
Back at the House of Lamentation, the brothers are complaining about being sore from the command. Lucifer is silent even when Mammon snaps at Leviathan, who's arrived to show his preliminary costume designs. The topic of MC's power returns again at breakfast the next morning. Satan is amazed at how much power MC holds, and a sore Beelzebub complains that he was made to sit on his knees in MC's room as he was yelled at for two hours.
Asmodeus changes the subject to the upcoming dance as part of the school festival, and wonders who MC will go with. MC then shows up, with Lucifer arriving shortly after, bringing news that he's received a bill for the restaurant's damages. He states that everyone will be responsible for an even share of the costs. MC, Mammon, and Beelzebub all get jobs at Hell's Kitchen to earn money for their share.
Meanwhile, Simeon is having trouble writing the play's script. Solomon asks how Simeon went about writing TSL, to which Simeon replied he used the seven brothers as character models. This gives him a breakthrough, and he stays up all night finishing the script.
At the Demon Lord's Castle, Barbatos is subtly encouraging Diavolo to return to his work. Similar to when he showed doubt about his past actions at the colosseum with MC, Diavolo asks Barbatos if he always chooses the best course of action. Barbatos tells him his actions are always correct, but Diavolo doesn't appear fully convinced.
As director of the play, Simeon is strict on everyone and frustrated that his expectations aren't being met. Solomon shows up to talk to MC about using their pacts to subdue the brothers at the carnival. He comments that the first time he put multiple demons under control at once, his whole body was sore, and asks if MC is all right. Diavolo then arrives, and he and MC practice a love scene for the play. He also asks MC if they are feeling okay, and tells them that they can talk to him anytime.
Later, at the House of Lamentation, the brothers — minus Leviathan, who was working on costumes — are tired from rehearsing, and begin to argue. Lucifer attempts to stop them, but is ignored. Instead, they all stop talking to each other. MC visits Leviathan in his room, who says this happened a lot while MC was gone.
The brothers then start to use MC to relay their messages between each other, witch Simeon thinks is amusing when MC tells him and Luke about it at RAD. With the help of Lord Diavolo calling an emergency meeting, Simeon tells everyone that they're going to have another retreat at the Demon Lord's Castle.
At the castle, Simeon announces who will room with each other, and makes sure to group together the brothers that are fighting with each other the most. Diavolo and Barbatos will have their own rooms, and Solomon was busy, so he couldn't participate. Everyone will be rehearsing the play during the retreat as well.
When dinnertime arrives, Barbatos instructs everyone on how to make Babylon curry, but another argument breaks out, and ingredients start being thrown about the kitchen. At Barbatos's encouragement, MC uses their pacts once more to make the brothers stay, this time including Leviathan. Afterwards, Beelzebub is upset because he wasn't able to have any curry, so Belphegor gives him some pudding he found in the fridge, which leads to the two being able to make up.
The next day, Belphegor takes MC aside to let them know he knows that Luke made the pudding, and knows it was MC's idea. He then asks if MC would go to the school festival's dance with him. MC's choice here — as well as the choices they make later when each of the other brothers ask them to the dance — will have an effect on the story later.
Rehearsal then begins, and Satan gets into an argument with Asmodeus, who wants to switch places with him. It ends with Asmodeus storms off, and MC following after. While Asmodeus is trying to explain his side of things to MC, they hear a hissing sound, and find Satan trying to help an injured cat that isn't cooperating. Asmodeus uses his charming ability on the cat to calm it down, and then apologizes to Satan about their argument earlier. The two make up and return to rehearsal.
After rehearsal ends, Satan thanks MC for talking with Asmodeus. He then asks MC to the dance, and again MC can accept or refuse. A new argument breaks out between Lucifer and Mammon this time, but Simeon breaks it up and asks them to at least stay focused during rehearsals.
Later, Asmodeus tells MC that Lucifer has a soft spot for Mammon, but that Mammon has "always been the naughty type." He explains that when they were angels, Michael was in charge of training Mammon, but had difficulties with him, and asked for Lucifer's assistance. Whatever Lucifer did won Mammon over, and Mammon's training was turned over to him. Asmodeus assures MC that they will get over this fight eventually, and changes the subject by asking MC to the dance.
The end of the retreat arrives with at least most of the brothers having mended fences. Simeon — who has already been harsh throughout — warns everyone not to slack off, because he's going to continue being strict on everyone until the play is over.
Leviathan is upset that Beelzebub's costume won't fit because he's been eating too much. He asks MC to watch him to stop him eating while he fixes the costume. MC agrees, and while together, Beelzebub asks MC to the dance. Luke then happens by, carrying a cake he made, and Beelzebub goes into a rage, chasing him back to House of Lamentation. Both he and Luke collide with Lucifer, causing the cake to fly into Beel's mouth.
A furious Leviathan shows up, who changes into his demon form and summons Lotan. However, doing so floods the house and ruins all of the costumes Levi had been working on. With MC's encouragement, he decides to re-make just one costume: MC's. He succeeds with MC's help, and then asks them to the dance.
The next day at RAD, Lucifer explains what happened to Solomon and Diavolo, who find it all amusing. Barbatos arrives then, and whispers something in Diavolo's ear. Diavolo says he has to leave on urgent business, and Lucifer assumes he'll be coming along, but Diavolo instead takes Solomon with him.
In RAD's courtyard, Mammon comments that Lucifer is trying to hide how upset he is, then insists that MC has something they need to ask him. MC can choose to ask him to the school dance or not. Either way, Mammon lets MC know that Lucifer tends to retreat to the music room and listen to classical music when he's upset, and suggests they visit him tonight.
MC does so, and Lucifer tells MC that he heard from Diavolo that he'll be unable to make it to the play tomorrow, so Simeon cut out his scenes. MC and Lucifer practice the play together, and MC can try to ask Lucifer to the dance or not. If they do, Lucifer interrupts and tells them to get a good night's sleep.
The play — titled "With Me" — begins the next day, and the choices MC made in Lesson 25 are reflected in how the story plays out. In the middle of the play, Lucifer changes his character's dialogue so that he can ask MC to the dance. The play continues, and MC's character is given a dagger so that they can kill the princess and marry Lucifer's character. They are unable to bring themself to do so, but Lucifer's character vows to renounce his royal birthright to be with them.
Once the plays is over, Little D. No. 2 shows up, and tells MC that Simeon wants to meet with them in the courtyard. MC goes there, and Simeon thanks them for their help in getting the brothers to do their best for the play. He then suggests that MC could either come with him to the Celestial Realm once their studies are finished, or he could come with them to the Human World.
MC heads back inside to find Diavolo and Solomon having just returned, and Diavolo asks who MC chose to go to the dance with. If only one of the brothers was chosen, they show up and take MC to the dance hall. If MC chose more than one, most of the brothers are upset by this — although Asmodeus, Beelzebub, and Lucifer seem more understanding — and MC ends up dancing with everyone. If MC chose none of the brothers, they end up going with Solomon.
After the dance is over, Lucifer finds Diavolo at the colosseum and asks him what has been going on. Diavolo replies that it isn't the right time to tell him yet. Lucifer also asks about the day he and MC were together when Leviathan's 3D escape game activated. Diavolo tells him that he, his brothers, and MC share a special bond, and that makes him jealous. Upset, Lucifer asks if he's suggesting that they don't share a bond with him as well, and Diavolo admits they do, but can't help feeling anxious. Lucifer tells him no matter what, he'll be by his side, and the two leave for the cast party.
The brothers are hanging out in MC's room, relived that the play is over, until Leviathan mentions that exams are coming up. Mammon, Beelzebub, and Leviathan complain about how difficult exams are, and Mammon tells MC they're lucky they're an exchange student, so their scores don't have to be as high.
MC encounters Lucifer in the hall, and he tells them he was able to speak with Diavolo about his recent odd behavior, then asks if MC is doing alright. He suggests they talk to Solomon about using the magic of pacts. MC meets with Solomon at RAD, and he shows them the Ring of Wisdom that was given to him by Michael. Wearing the ring gives him the power to control demons, but when he was still new to having pacts, the energy needed to use them made him incredibly sore. He finds it odd that's not the case for MC, but they're interrupted by a text on MC's D.D.D..
The text is about an emergency meeting that MC also attends, where Diavolo announces that for the upcoming exams, MC will be given the same pass/fail standards as the regular students. Mammon and Belphegor argue that's too much for MC to handle, but Lucifer tells Satan that he will be tutoring MC for the exams.
Tutoring with Satan begins with seductive speechcraft, and Leviathan joins due to his poor scores last exam. Satan explains the steps to seducing a human are to "look at them with a kind, friendly smile" and to "tell them that I'm a demon." Satan then tells Leviathan to seduce MC, but when he tries, tells him he did a poor job, and gives his example of seducing MC. Then it's MC's turn to seduce Satan, who passes if they choose to meow at him. Afterwards, in Leviathan's room, MC helps him practice by pretending they're in a dating sim, and he asks MC to stay the night so practice can continue.
The next lesson focuses on curses and hexes, this time with Mammon joining. They start with the basics, like explaining the word for "curse" in Latin is "Imprecatio." Then Satan asks MC to try cursing Mammon. MC messes up, instead causing Mammon to be overcome by desire for them, so Satan kicks him into unconsciousness. He then tells MC that performing curses takes a toll on the body, and uses a spell to fix MC's dizziness. MC uses the same spell on Mammon later to take care of his soreness.
Out in the Devildom, MC comes across Luke and Simeon, who suggest that they should all study together, though Simeon has to cancel later. This time, the focus is on magical potions with Beelzebub joining, and they're in the twins' room instead of the library. Satan again starts with the basics, like how the elixir of cerebral stimulation requires powdered unicorn hoof, bittergrass root, and caladruis blood as ingredients.
When making the potion, Belphegor has to stop Beelzebub from eating the ingredients. In the middle of brewing, however, he still drinks MC's potion. The unfinished potion makes him behave like a cat, and MC keeps him occupied while Satan researches a cure. After he's cured, Mammon suggests giving the potion to Lucifer. MC makes another potion, but Leviathan makes Mammon drink it instead. Because he didn't drink all of it, he's still able to talk, but also meows like a cat.
Lessons with Satan continue, this time with Devildom history. Both Luke and Simeon are able to join this time, while Solomon is at the Demon Lord's Castle again. Asmodeus was also meant to join, but he skipped tutoring to go shopping with Mammon.
Satan explains that the Devildom came into existence at the same time as the Celestial Realm, and then covers some basic trivia, such as shortly after the Devildom came into existence, its surface was covered in a forest. There is also a relief sculpture at the entrance to the Devildom royal tomb that depicts a three-legged crow.
At some point during Satan covering the Great Celestial War and the aftermath, both Luke and MC fall asleep. Simeon comments that he thinks its amazing that after such a violent history, angles and demons can now study together in peace.
Later in Asmodeus's room, Asmodeus complains to MC about the work Satan gave him for skipping his tutoring session. Then the next day, exams begin at RAD. Day 1 covers magical potions and Devildom history. Belphegor falls asleep mid-exam, but only because he finished early. Before leaving, he invites MC to hang out in the planetarium that night. On their way back to the House of Lamentation, MC crosses paths with Solomon, who is again on his way to the Demon Lord's Castle.
After the first days of exams, Mammon, Leviathan, Asmodeus, and Beelzebub are at The Fall when Asmodeus mentions that tomorrow's exam is seductive speechcraft. The idea of practicing with MC before the exam encourages each of them to head home. Meanwhile, MC meets with Belphegor in the planetarium, who tells them about the twin stars that appeared in the sky after the Great Celestial War ended, and how they represent him and Beelzebub.
The exams on day 2 are curses and hexes and seductive speechcraft, and in both, MC must choose one of the brothers as a partner. Once exams are over, there is another student council meeting that MC also attends. If MC was able to answer at least four of the exam questions correctly, their exam score is excellent and Diavolo praises them for how well they did. If they answered at least two questions correctly, they passed with average exam results. If fewer than two were correct, Diavolo says they were only barely able to pass, but Mammon, Leviathan, and Beelzebub reassure MC that it's okay and they did well enough.
Mammon announces that it's time to party now that exams are over, and everyone heads to The Fall except Lucifer, Diavolo, and Barbatos. Barbatos brings Lucifer some tea, and Lucifer asks him if he can tell him anything about Diavolo's recent behavior. Barbatos refuses, then warns Lucifer to be prepared in case he'd ever face the decision of staying by Diavolo's side even if it meant hurting those closest to him.
After partying, everyone makes it back home where MC hears music playing, and finds Lucifer in the music room. He tells MC that he feels like something bad is happening, but Diavolo won't tell him yet what's going on. He then brings up the play from earlier, and asks what MC would do when faced with the choice of duty or love, but then tells them to forget what he said.
At some point after the botched potion that MC made caused both Beelzebub and Mammon to have cat-like behaviors, Mammon tasks MC with giving the potion to Lucifer. MC goes to Lucifer's room and gives him a drink laced with the potion, but nothing happens. He tells MC that he's able to resist the effects of most potions and elixirs, then asks MC if they'd rather be punished by spending the night with him, by pretending to be a cat, or by meowing as cutely as they can.
Mammon, Leviathan, and MC are playing video games in MC's room — with Beelzebub cheering them on while snacking — when Leviathan mentions a time loop game called "The House of Sorrow" is releasing next week. The game's murder mystery story is based on events that happened in the House of Lamentation back when it was still in the Human World. Suddenly, Asmodeus bursts into the room to announce there will be a bloody moon this weekend.
In the dining room, the brothers explain that a bloody moon is a night when the Devildom moon turns red. During the bloody moon, the bloody moon competition is held, when students at RAD vote to decide who the most honored and respected demons are. Everyone expects Diavolo and Lucifer to take first and second place, as they always do, but Asmodeus seems upset about something. He invites MC to his room, where he tells them he wants to come in first for this year's competition, and asks for MC's help to do so.
Asmodeus also asks for help from Satan and Belphegor, as they're members of the "Anti-Lucifer League." The two agree, and suggest plans to sabotage Lucifer's reputation, but in the end the plan is to improve Asmodeus's image. They decide to make a promo video for him to upload on DevilTube, and Satan asks Mammon to help direct it due to his experience as a model.
They set up to film in Asmodeus's room, because Mammon wants to focus on letting people see the "real Asmodeus." When the video is uploaded, it does as well as all of Asmodeus's other video, but no better. Next, Satan suggests throwing a fundraiser party at Ristorante Six. Asmodeus struggles with taking Mammon's advice from earlier, but just sounds awkward. Meanwhile, they find out from a chat Beelzebub sends that Lucifer is at Hell's Kitchen and is paying for everyone in the restaurant.
The next day, Satan reveals that the RAD Newspaper Club released an article about Lucifer treating everyone at Hell's Kitchen, which upsets Asmodeus, so MC goes to Solomon to asks for advice in cheering him up. He suggests shopping, which MC and Asmodeus do. This does cheer Asmodeus up, until a text from the RAD Newspaper Club announces that Diavolo has dropped out of the competition, and is backing Lucifer instead.
After returning to the House of Lamentation, MC talks to Lucifer in his study about the news. He tells MC that he still doesn't know what Diavolo is doing, and didn't know he was dropping out until asked for an interview. He also explain that he paid for everyone at Hell's Kitchen earlier because it was the owner's birthday, and doesn't really care about the bloody moon competition.
Asmodeus still refuses to give up, but after a tense breakfast, another text from the RAD Newspaper Club announces that after Lucifer, Beelzebub is in second place, with Asmodeus in third.
Meanwhile, Simeon brought some cake sent to him by Michael to the Demon Lord's Castle for Diavolo to try, though his meeting is something he's keeping a secret from Luke. He brings up the secrets Diavolo and Solomon are keeping, and delivers a message from Michael that if these secrets affect the Celestial Realm, then the angels will intervene.
MC and Belphegor are playing Old Maid in the twins' room while discussing the current results of the bloody moon competition, and why Beelzebub just being himself is why he's currently in second place. MC then heads into the hallway and finds Asmodeus trying to get into Leviathan's room. MC says the password needed, and Asmodeus asks Leviathan to sew ten outfits that he designed. Asmodeus wants to throw a party tomorrow with a fashion show, and after saying he and MC will help, Leviathan begrudgingly agrees.
The next morning, Mammon find Leviathan, Asmodeus, and MC asleep on the floor in Leviathan's room, but Lucifer tells him to let them sleep. The party begins that night, with many famous people invited. Asmodeus announces the theme of today's show is "Keeping It Real," and that the outfits in the fashion show represent true "Asmo styles."
Solomon compliments MC for making Asmodeus feel better, and when Luke says that he won't be voting for any demon in the competition, Simeon points out that only demons are allowed to vote anyway. Solomon then gets a call from Barbatos, and suddenly has to leave. Lucifer then appears, and when Simeon asks about a meeting, explains that Diavolo had to cancel as something came up last minute. Asmodeus notices him there, and scolds him for trying to keep MC to himself before pulling MC away with him.
The two take to the dance floor, where Asmodeus tells MC that he's in a great mood, and it's all thanks to MC for helping him realize how to be true to himself. However, the next day at RAD, all he can do is worry about the votes. The voting takes place, and the results leave Asmodeus and Lucifer tied for first with only one vote left...Lucifer's. Asmodeus is certain he's lost, but Lucifer votes for Asmodeus, and Diavolo announces him the winner.
At the House of Lamentation, Asmodeus can't stop crying and telling Lucifer how much he loves him. At first he'd been upset, because he thought Lucifer voted for him out of pity. Instead, Lucifer explained that his talent for fashion design and being able to charm almost everyone he meets makes Lucifer respect him for his abilities. Belphegor then notices that Leviathan is missing, and Satan says he hasn't seen him all day.
MC and Asmodeus head to Leviathan's room to try and find him. On the way, Asmodeus thanks MC again for helping him with the competition, and says he now better understands both himself and Lucifer. They then knock on Leviathan's door, but suddenly hear him scream. The two rush into his room to find him unharmed, but upset about something, and saying Lucifer's going to kill him.
Out in the primeval forest in the Devildom, Diavolo, Barbatos, and Solomon examine an entire cliff that has collapsed. Barbatos also mentions that a few days ago, there was an incident at Demon King's tomb. Solomon suggests letting Simeon and the Celestial Realm know about this. Diavolo states that he has difficulty dealing with Simeon, and asks Solomon to speak to him in his stead.
When Barbatos asks about what to do with Lucifer and his brothers, Diavolo tells him that they should keep this from them a little longer, despite knowing it's a bad thing to do. He wants to have proof that MC is the source of what's happening before telling them anything.
In the library, Lucifer demands to know what Leviathan has done, and he admits the time loop game "The House of Sorrow" had a charm cast on it by developers to keep people from playing it before the official release. Because he loaded up the game early, a message appeared saying the current day will repeat endlessly until whatever someone was wishing for the moment the charm took effect comes true. Everyone's memories will also be reset each day.
Lucifer tasks Leviathan with making everyone's wish come true, and both he and MC retreat to MC's room to decide who to start with. Leviathan refuses to start with himself, and suggests starting with Lucifer instead. Lucifer says that he learned Mammon was a bookie for a group of RAD students during the bloody moon competition and made money doing so. He wished that Mammon could become a proper demon, and when asked what that means, he says a "proper" demon is honest and doesn't make things difficult.
Leviathan produces a bangle that forces wearers to tell the truth, and can only be taken off by the person who put it on. He'd gotten it from Satan, who planned to use it to prank Lucifer. He puts the bangle on Mammon, who admits that he likes and respects Lucifer, but doing so doesn't break the time loop.
Next they try to grant Mammon's wish, and when he refuses to admit what it is, the bangle is put back on him. He again tells the truth, and says that he wanted MC to only be sweet and happy when alone with him. Leviathan runs off, leaving Mammon wearing the bangle, and because he can't stop admitting truths out loud, hides with MC in the bathroom.
He tells MC that he likes them, and his wish is to hear them say they like him too. MC does say they like him — though how they mean it depends on the player's choice — but suddenly Leviathan appears from the bathtub, because he was hiding there when Mammon and MC came in.
Upset that Mammon's wish didn't break the time loop, Leviathan next moves to granting Satan's wish. He and MC find him in the living room, and he says that his wish was to see Lucifer kneel at his feet. Leviathan thinks the best way to get that to happen is by accident. He gets Lucifer into the room, and MC drops a magazine at Satan's feet. Asmodeus picks it up, ruining that plan, so Leviathan tells Lucifer his shoe is untied. Not knowing who he's talking to, both Lucifer and Satan bend down, knocking their heads together.
Leviathan then admits what Satan's wish it to Lucifer, who doesn't even hesitate to kneel before Satan, telling him it's sweet that's all that it takes to make him happy. Satan doesn't seem happy with this, but his wish was still granted, and the time loop remains.
Meanwhile, at Purgatory Hall, Luke brings Simeon some tea and cake, who is working on writing a spin-off to The Tale of the Seven Lords. Despite the recipe being new, Simeon gets the feeling he's had this cake before. Solomon then appears with some food that he's made, and when Simeon suggests letting everyone at the House of Lamentation try it instead, he tells them about Leviathan triggering a time loop.
Asmodeus's wish is next to be granted, and his wish is that he wants to charm MC as a reward for helping him win the bloody moon competition. Asmodeus's charming ability doesn't work on MC, but he, MC, and Leviathan go to his room to try anyway. When it still doesn't work, he gets sidetracked and pulls out a photo album from when he was an angel.
When looking at the pictures, Asmodeus claims that MC is emitting an aroma of attraction. This makes him feel like he was able to charm them just a little, but that's another wish granted without fixing the time loop. Leviathan and MC move on to Beelzebub, whose wish is to drink a "siren's song." To prepare the cocktail, you have to listen to a siren's song, which makes the listener lose their mind and want to jump in the nearest body of water to drown. Leviathan suggest using a record Lucifer has of a siren's song, and they all go to the music room to find it.
Meanwhile, Lucifer visits the Demon Lord's Castle because Diavolo invited him for tea. Barbatos greets him, and is amused about hearing their issues in dealing with the time loop. Diavolo is happy that Lucifer still meets with him despite having other things to deal with, but when he jokes it wouldn't be so bad to repeat this day, Barbatos reminds him of the stack of paperwork he still needs to sign after tea is over.
Leviathan and Beelzebub look through Lucifer's records, but don't let MC help in case they touch one of the many cursed records. The records is found, and Leviathan makes the drink wearing earplugs while Beelzebub and MC cover their ears. Beelzebub then drinks the cocktail, and the time loop still isn't fixed.
Leviathan and MC find Belphegor in his room, who says his wish is to nape with MC. He then orders Leviathan out, and MC sits on the bed while he rests his head in their lap. He isn't tired, however, so asks MC to sing him a lullaby. MC sings the siren's song, and Belphegor tells them that a long time ago he, Beelzebub, and Lilith listened to that song once.
Belphegor eventually falls asleep, and Leviathan returns to check on them. With another wish granted, only Leviathan's wish remains. He finally admits that his wish is to play games all night alone with MC. They do so, and after falling asleep, wake up to find that the charm is gone.
At breakfast, Lucifer is exhausted, and wishes for a break from the constant mayhem being caused. Mammon then shows up and tries putting the charmed bangle on Lucifer, and Satan succeeds after he fails. Lucifer promptly breaks the bangle, but before he can deal out punishments, Beelzebub enters the room and tells Lucifer they have a problem.
In the music room, Beelzebub explains that he wanted to have one more siren's song, and tried making the cocktail himself. However, the earplugs he was wearing fell out, and under the song of the siren's spell, he thrashed around until he bumped the needle of the record, stopping the music. The record player is still turned on, and now with everyone in the room, the record starts playing again. Everyone races to the bathroom in search of water, nearly trampling a visiting Solomon, who fortunately performs a spell to end the curse. Unfortunately, he was visiting because he brought food he made for everyone to try.
Before anyone has to eat the food, Lucifer arrives with one of his records broken in half. The record, the "Hymn of the Reaper," is a song from an opera of the same name, sung by the reaper as they extinguish the candle representing the soul of the protagonist. Everyone worries that because Beelzebub broke the record, he's incurred the wrath of the reaper, who now might extinguish his soul at any moment.
Satan explains to MC that housed within a Reaper's Cave are the Life Candles representing the souls of humans, demons, and angels. Belphegor suggests going to the cave to check Beelzebub's candle, but Satan points out that no one know where it is. Except Solomon does know, and they all head outside so he can draw the magic circle needed to get there.
Solomon warns that the reaper is likely to accuse them of trespassing, but doesn't give anyone time to think on that before saying the spell to transport them to the cave. Once everyone lands, Leviathan find a message written in blood directed at Solomon. The message states that if he tries "sneaking inside" while the reaper is gone, they will destroy his life candle. When Leviathan asks Solomon what he did to make the reaper so angry, he replies that he can't think of anything.
Mammon suggests that the reaper not being present is a good thing, as now they can check Beelzebub's candle and leave without being noticed. Before they enter the cave, Solomon tells everyone that there are rules that must be followed. Each level of the cave has a different rule, and if broken, there will be a terrible punishment.
Hearing this, Beelzebub wants to go alone, then when everyone insists on going with, argues that MC is particularly endangered, as they're a human. Asmodeus argues that MC is no ordinary human, as they are powerful enough to use their pacts with the seven brothers as needed.
The first level of the cave looks like an open field, and the rule for this level is "Don't look back." To trick them into breaking the rule, everyone hears different voices behind them, calling them to look back. Leviathan, hearing the voice of Ruri-chan, looks back, and is turned into a Little D..
Level 2 of the cave looks like a library, and the rule is "Do not touch." Beelzebub notices a mark on Mammon's wrist that looks like Midas's Crest, the bearer of which can turn whatever they touch into gold. It's not really the crest, but Mammon still attempts to touch things, and is turned into a Little D. as well. Satan meets the same fate immediately after, as he was tricked into trying to pick up what he thought was a kitten meowing at him.
Solomon comments that he'd assumed something more terrible would happen to those who broke the reaper's rules, and wonders if something is protecting the brothers. Mammon then asks Solomon if he'll give him a real Midas Crest. After Mammon refuses Solomon request for a pact in return, he agrees instead to help Solomon forge a pact with Lucifer. He changes his mind, however, when Asmodeus points out that with the crest, he wouldn't be able to touch MC anymore.
Asmodeus is curious about the reaper, and asks Solomon what they're like. He replies that even though they've known each other for over a thousand years, there's much Solomon still doesn't know about them. MC is shocked that Solomon is so old, so he explains that long ago, he was researching new forms of magic, but made a mistake that led to him being unable to grow old or die. Lucifer calls for everyone to keep moving, but MC thinks they see Solomon take a book off one of the shelves as they head out.
Level 3 of the Reaper's Cave has the rule "No talking," and because their D.D.D.'s don't work in the cave, texting also isn't an option. Everyone tries communicating with each other by thoughts, which doesn't work well for any of the brothers besides the twins. They all still manage to understand MC, however. Satan, Mammon, and Leviathan are able to speak aloud because they're already Little D.'s. Asmodeus opens a door into a closet full of designer clothes that he can't help but start talking about, and is turned into a Little D. as well.
Level 4 of the cave is a series of rooms filled with food, and the rule is "Do not eat." Beelzebub is able to resist the temptation until Solomon spots a dish just like one MC made during their retreat at the Demon Lord's Castle. To save his brother, Belphegor eats the dish instead. Solomon notices Lucifer look pale, and he replies that his head hurts.
They reach Level 5 of the cave, which has no rules, and Belphegor finds the Life Candles representing the seven brothers, with MC's candle right next to them. Beelzebub's candle, however, is nearly burned down and is burning much faster than the others. He asks if there's a way to summon the reaper so he can explain and apologize, but instead, Lucifer pours some of the essence of life from his candle into Beelzebub's. Each of the other brothers follow suit, even though this will shorten their own lifespans.
This buys Beelzebub some time, but his candle is still burning too fast. MC then pours a single drop of their candle's essence into Beelzebub's, and in a burst of light, his candle returns to normal again. Solomon transports everyone back to the House of Lamentation, and Lucifer heads inside to rest in hopes of treating his headache.
MC is able to ask Solomon several questions. When asked about the stolen book, Solomon explains he and the reaper have competitions sometimes. As he won the last one, he's allowed to take one item as a prize, which is why he wasn't punished for breaking the "Do not touch" rule. Solomon also explains that he once invited the reaper to eat some of his cooking, and they've disliked him ever since "for some reason." When asked about his age, Solomon admits he no longer remembers how old he is.
Once back in the house, Asmodeus asks Solomon to change everyone turned into a Little D. back to normal, which he does, and Beelzebub then takes MC aside to thank them for what they did in the cave. Solomon interrupts them, however, and tells them that Diavolo has been keeping secrets from them. He doesn't agree with that decision, and starts to tell them something, only for everyone to hear Lucifer scream. They all rush to the dining hall to find Lucifer collapsed on the floor.
Meanwhile, Diavolo, and Barbatos, and Simeon examine a hole in the forest that has grown larger in the past days, and Diavolo tells Simeon that the Royal Tomb has collapsed as well. Nothing like this has happened before, and it's Solomon's opinion that MC is the cause.
Simeon asks why Diavolo's kept it a secret from the brothers, and why Lucifer in particular is so important to him. Diavolo gives a vague non-answer, and Simeon tells him that he should have told Lucifer about these happenings right away. Barbatos agrees, and Diavolo decides to send Lucifer a message to come see him so that he can tell him everything.
An unconscious Lucifer is carried to his room, where Belphegor brings up that he kept mentioning his head hurt while in the Reaper's Cave. Solomon had left to fetch Diavolo, and returns with him as well as Barbatos, Luke, and Simeon. Diavolo is distraught over seeing Lucifer, and exclaims that this is all his fault. He asks for MC's help, and everyone but Luke — who is keeping an eye on Lucifer — heads into the living room.
Diavolo explains that unprecedented phenomena have been taking place in the Devildom, such as the Royal Tomb collapsing and holes opening in the forest. Solomon admits this is why he brought MC to the Devildom, and that similar phenomena have also been happening in the Human World. Simeon adds that this is happening in the Celestial Realm as well, though at a lesser extent. Diavolo then bluntly states that he and Solomon believe MC is the cause. Luke then runs in to let them know Lucifer is awake.
Initially, everyone is relieved that Lucifer is awake again, but when Lucifer asks who they are, they realize that he has amnesia. Barbatos puts Lucifer back to sleep, and Luke again stays to watch him while the rest return to the living room. Diavolo continues his explanation, and tells MC that being a human, the distant descendant of an angel, and having pacts with all seven of the brothers, means that MC shares deep bonds with all three worlds. After hearing Solomon's theory about these bonds, Diavolo subjected MC to exams at a higher standard to test their powers.
The test results didn't show MC to be capable of powerful magic on the surface. Because MC cannot fully control the power granted by the "ring" their connection to the three worlds creates, MC's powers has caused a negative impact on all three worlds without realizing it. Diavolo states there are two possible ways to fix this: MC gains the ability to control their powers, or the "ring" is severed.
The only magic item that could help MC control their powers is the Ring of Light. This ring once belonged to Lucifer, but he lost it during the Great Celestial War. Severing the "ring" would require the power of the Night Dagger Solomon took from the Reaper's Cave. Using it would mean MC's pacts with the brothers would also be severed, and as Diavolo tells Mammon, once a demon's pact is broken, it's permanent. However, severing the ring might also return Lucifer's memory.
After announcing that Solomon will perform the ceremony needed to sever the ring, Diavolo apologizes to MC and hugs them. Solomon needs to do research first, and leaves along with Diavolo, Barbatos, and Simeon. Before Luke leaves also, he tells MC that Lucifer was saying their name in his sleep.
Back in Lucifer's room, Asmodeus is showing Lucifer a photo album from when they were in the Celestial Realm, but it only has pictures of himself. After Lucifer complains, he leaves to get different pictures, but reassures MC before he goes that even without a pact, their relationship will still be the same.
Lucifer tells MC he now knows what Asmodeus is like, but asks about his other brothers. MC has the choice to provide a more positive or negative opinion on each of them. He then asks about his relationship with MC, with options given to be romantic or not. Beelzebub then brings Lucifer some food, and tells him about how he gave some of his Life Candle's essence to him. He then gives both Lucifer and MC a hug.
Then next day, MC finds Lucifer in the attic with Belphegor sleeping with his head on Lucifer's lap. MC joins them, and the three nap together. Later, Mammon is talking to MC, and the two find Lucifer in front of Leviathan's door. MC provides the correct secret phrase about the second lord "having incurred the wrath of the Lord of Corruption."
Lucifer wants to play video games, so the four of them play "Super Smash Devils" together, with Lucifer insisting that he won't quit until he manages to beat Leviathan. Leviathan takes a moment to tell MC that even without a pact, the two of them will still get together and game.
While all of this is happening, Little D. No. 2 finds Barbatos to tell him Diavolo is acting strange. Barbatos find him and asks him what's wrong, and Diavolo replies that he want to check on Lucifer, but doesn't feel he has the right. Barbatos disagrees, but advises to trust Lucifer's brothers and MC to look after him.
Satan tries to convince Lucifer not to play cards with Mammon because he's worried Mammon's trying to take advantage of him having amnesia. Lucifer won't be convinced, so Satan asks MC to go with him. The two join Mammon in his room, and Mammon suggests playing "The Witch and the Black Cat," a card game where two players try to take each other's face cards. If Mammon wins, he gets to use Lucifer's credit card for one day. If Lucifer wins, he gets MC to himself for one day, though he tells MC he'd ask for something else if they didn't like the idea.
The card game begins, but Lucifer is distracted by regaining memories of Mammon's Demonio 666 Lexura. The color for the car Mammon wanted was limited edition, so Lucifer secretly asked Diavolo to help him get it for Mammon. He then told Mammon that he found a dealer who had the car in stock.
The game ends with Lucifer winning, who then leaves MC with Mammon. Mammon tells MC that even if their pact is severed, he's still their first demon. Later in the library, he tells Leviathan and Satan that Lucifer will have MC to himself tomorrow. The three start making plans to intervene, but Lucifer shows up and thanks them for helping him while his memories are gone. This makes them change their minds about interfering with him spending time alone with MC.
The next day, Lucifer and MC are on their way out of the house when they run into Solomon. He says he wanted to talk to MC, but he'll just come back tonight. He also suggests they go to Devil's Coast, as it's the last day they're open. They take Solomon's advice, and end up riding the ferris wheel just as they'd done the last time. Lucifer tells MC that even without his memories, MC is special to him.
After the two return to the House of Lamentation, MC finds Solomon waiting for them in their room. He tells them he researched the Night Dagger only to find its magic power has waned over the years, and so would not be strong enough to sever the ring of MC's powers. The only way to restore the dagger's power is to kill a demon with it and have the dagger absorb said demon's power.
Solomon hands MC the Night Dagger, and tells them to use is on Lucifer, but then says he's just kidding. He says that he has always put the interests of the Human World above all else, but he doesn't want MC to hate him. Lucifer then enters the room, who overheard everything.
Lucifer tells Solomon to leave, then holds onto MC's hand and tries to get them to use the dagger on him. However, Simeon appears and puts the Ring of Light on MC's finger. MC sees a blinding light, and a disembodied voice speaks to them, saying they're jealous of MC, and that they loved Lucifer and his brothers, but lost them. They then tell MC the Ring of Light will protect them now, and returns MC to their room.
At the Demon Lord's Castle, MC, Luke, Simeon, and Solomon all talk about recent events. Now that MC has the Ring of Light, the chaotic ring of MC's connection to the three worlds has stabilized. Lucifer's memories have also returned, when then unleashed his anger on both Solomon and Diavolo.
Solomon asks MC — who now ranks as a sorcerer with powers as strong as his — if they'd help him protect the Human World by helping him decide what to do in future complicated situations. MC agrees, then Solomon asks Simeon how he was able to find the Ring of Light. Simeon explains that he suspected Michael had the ring, so went to the Celestial Realm to "borrow" it from him. Barbatos then arrives to tell them "the preparations are complete."
Meanwhile, Diavolo attempts to explain to an angry Lucifer why he'd kept secret that MC might be the cause of the destructive phenomena. Solomon comments that this is why he advised Diavolo to tell Lucifer, but Simeon points out that he also didn't tell Lucifer, and that he tried to convince MC to stab him with the Night Dagger.
Diavolo comments that Lucifer sounds more rough now than he did before, and that Lucifer should always talk to him in this more "real" way. Lucifer isn't happy about that, so Diavolo says that he got him a painting from the famous unknown Devildom artist John Smith. While still angry, Lucifer is also moved that the painting he'd wanted is now his. As Solomon tries to make his exit, Lucifer's ire moves on to him.
At the Demon Lord's Castle, Diavolo tells MC how surprised he was when Simeon told him that they'd received the Ring of Light's blessing. MC then remembers waking up just after being given the Ring of Light to the brothers bursting into their room, worried because Beelzebub said that he saw Celestial Realm light coming from there. Lucifer warns them to be quiet if they don't want a repeat of what happened at the carnival when MC told them all to "stay." Everyone realizes this means that Lucifer's memory has returned, and an exhausted MC falls asleep.
Back in the present, Diavolo thanks MC for saving both Lucifer and the Devildom, and tells them there's a party in their honor today. Everyone is in their demon forms for the event. Leviathan mentions he's surprised that Lucifer still remembers what happened while he had amnesia. Satan and Belphegor both say that they preferred Lucifer when he had amnesia, but Asmodeus calls them out on actually being relived that Lucifer's back to normal.
Diavolo then asks MC to dance with him. He tells them that as the living embodiment of bonds between the three world, MC is a very important person, and he feels that he can place his trust in MC. He wants to say more, but the song ends, and Luke asks to dance with MC next.
The next morning at the House of Lamentation, Lucifer is mostly the same as before, but now seems even closer to his brothers. Out in the Devildom, MC runs into Luke, Simeon, and Solomon, who reminds everyone that they'll be returning home soon. MC brings this up to the brothers when at RAD, and Asmodeus suggests asking Diavolo if MC can stay longer. When MC does this, Diavolo points out they have a life in the Human World to consider. Afterwards, Belphegor suggests asking Solomon to teach MC how to teleport between the Devildom and Human World.
Solomon tells MC they have the raw power to learn teleportation, but lack the skills, so MC will have to start with the basics first. He asks MC to become his pupil and learn magic from him, though he points out learning to teleport could take years. Instead, he suggests learning to use their pacts with the brothers to summon them to where they are.
He explains further that if the brothers each give MC "something that is dear to them," their gifts will act as permits that would allow MC to summon them across worlds anytime. MC returns to the House of Lamentation, then they hear a loud noise. They find Satan in his room beneath a collapsed pile of books. He blames Lucifer for this, because he'd asked Satan to tidy his room.
MC helps him clean, and explains what they learned from Solomon. Satan then gives them the Forbidden Book that causes people to switch bodies when two people touch it at once. The magic has faded, so it no longer has that power, but it's connected to an important experience to Satan, so he wants MC to have it.
At the house's entrance, MC finds Asmodeus lugging boxes filled with clothes he hasn't worn recently. Lucifer ordered him to get rid of what he doesn't need. MC starts to ask him about getting a gift from him, but Asmodeus beats them to it, having already heard what was going on from Solomon. He doesn't know what to give MC, but the two decide to take pictures together, and both save a copy to their D.D.D.'s.
Next, MC finds Belphegor trying to hide because Lucifer told him to clean the attic, and they ask him for a pact gift. He gives them his star, one of the two twin stars in the Devildom sky that represent himself and Beelzebub. He then says next time they'll look at the stars together in the Human World.
Later, Diavolo comes to the House of Lamentation to visit MC, and tells them "a friend of his" has been acting cold towards him because he was keeping secrets from said friend. He asks MC for advice, then Barbatos tell him that his tea is ready. He also comments on MC doing a good job advising Diavolo. Lucifer then asks Diavolo to at least seek MC's advice about him when he's not in the same room.
Leviathan brings a box of games and DVDs to MC's room because Lucifer asked him to declutter his room, so he wants MC to take them back to the Human World. Then, for his pact gift, he presents the script to "With Me," the play they performed for the RAD school festival. He tells MC they have to summon him whenever there's any event he wants to go to, then gives MC a hug, and tells him they'll still game online together every night.
MC then finds Beelzebub in the kitchen, because Lucifer told him that he could eat anything but the emergency rations. He knows about the pact gifts, and that Belphegor gave MC his star, so he wants to also give MC his star. He also says he was once leader of Lucifer's personal guard when they were in the Celestial Realm, so if MC gets into trouble in the Human World, they should call him.
MC next finds Mammon in his room trying to avoid Lucifer, who told to repay any debts he has in the Devildom right away. He too knows about the pact gifts already, and gives MC one of the "Harrison Porter" keychains they bought when they went to the Human World together before. He then tells MC that when they summon him to the Human World, he'll refuse to leave and stay by their side.
Later, MC hears music coming from Lucifer's secret study. They find Lucifer there, and he shows MC the Gold Hellfire Newt Syrup he has, telling them he mixed it with the Demonus he's drinking. MC gives him an order to either kiss them, or give them something precious to him. Either way, for his pact gift, he tells MC they already have it: the Ring of Light. He's happy that something once belonging to him now keeps MC safe.
The next day, MC visits Purgatory Hall for some tea, and Solomon tells them once they return to the Human World, he'll teach them the magic needed to summon the brothers. MC then visits the Demon Lord's Castle with Luke, who's going to see Barbatos about a new recipe. Luke and MC are greeted by Barbatos at the castle, then Diavolo appears and asks to talk to MC. They go to the garden, where Diavolo admits that he doesn't want to send MC back to the Human World. He again is interrupted in trying to tell MC something when Luke shows up with some muffins he made.
On MC's last day in the Devildom, everyone throws MC a surprise party. Diavolo teleports them all to The Fall, where he'll be paying everyone's tab. When taking a break from the party, Simeon tells MC that he, Luke, and Solomon decided to leave today instead of tomorrow. He explains that Michael wants a report on what's happened during the crisis caused by MC's powers. Solomon also says he wants to see the situation in the Human World for himself.
Luke openly admits he'll miss the Devildom, and that thanks to MC, he realizes that he needs to make some changes in himself, and that it's not right to condemn someone just for being a demon. The brothers then find MC and bring them back to the party.
Early the next morning, MC wakes up inside a sack being "kidnapped" by the brothers, minus Lucifer. The sack is opened when everyone is inside the underground tomb, where an emergency escape route leads to the far reaches of the Devildom. Everyone is nearly attacked by Cerberus, who is guarding the tomb, but Lucifer appears and tells him to sit. He then gives them instructions for how to find the escape route, but as soon as they make it to the outskirts, they're met by Diavolo and Barbatos.
Diavolo wasn't surprised the brothers pulled this stunt, but is surprised that Lucifer helped. He tells everyone that he doesn't want MC to be a demon or an angel, but a human who can someday work with himself to bring harmony to the three worlds. He wants MC to better understand all three worlds, not just stay in the Devildom. Barbatos then opens the portal to the Human World, the brothers say their goodbyes, and MC leaves.
After MC is gone, the House of Lamentation is back to normal, meaning everyone is arguing and missing MC. Lucifer asks if everyone is done tidying their rooms, then tells everyone to start packing, because they're going to the Human World.
MC runs into Solomon in a Human World park, where he asks MC if they're keeping up with the homework he gave them on fundamentals that sorcerers need to know. He also suggested earlier that MC take a babysitting job, and hands them the address of the people looking to hire MC. MC goes there to find a manor, and the door is answered by Asmodeus. Leviathan, Satan, Beelzebub, and Belphegor are there as well, and MC is so shocked that they use their pacts to make everyone "stay."
After calming down, Asmodeus explains that they're all spending their vacation in the Human World, and wanted to surprise MC, so they told Solomon to contact them. MC then finds Mammon hanging from the music room's ceiling because he gambled away all their money — and gave the deed to the house to some loan sharks — as soon as he got here. MC gets him down, then Asmodeus gives MC a tour of the manor.
The first room they visit is Asmodeus's private bathroom in the House of Lamentation. When the brothers decided to stay in this manor, they asked Barbatos to create portals to their favorite rooms in their home in the Devildom. Satan then finds them, and takes MC to the manor's home theater. He mentions that he and his brothers had been in the Human World since last week, but Asmodeus and Mammon insisted they keep it secret from MC until they could think of a way to surprise them. Leviathan comes in yelling about an emergency in the kitchen, and tells Satan to go there. He then asks MC if they want to see what it's like outside.
Leviathan shows MC the outdoor pool, then they go to his room to see Henry and game, but Belphegor interrupts, telling Leviathan he still has "a job to do." He then takes MC to their room from the House of Lamentation, which Barbatos also made a portal to. They both fall asleep there, then MC later wakes up in the living room in Beelzebub's arms, who'd carried them there.
The two continue to the twins' room, where Beelzebub retrieves some party crackers. Lucifer then sends him a text telling him to bring MC to the manor's balcony. Everyone is there to throw a party inviting MC to stay with them at Serenity Manor. Lucifer later asks MC to slip away with him, which MC can accept or refuse. If they do leave with Lucifer, he admits that he was planning this vacation to the Human World since MC asked them all for pact gifts.
After most everyone gets the idea to wake MC up that morning, Lucifer asks MC to go wake up Mammon. Then while eating breakfast, Lucifer reminds everyone they need to decide who will be in charge of what chores around the house. This leads to a "rock, paper, scissors" tournament involving Beelzebub calling forth a Rock Giant and Leviathan summoning Lotan.
After chores have been decided, another "battle" of rock, paper scissors takes place over the bathroom order. Asmodeus is excluded this time, as he has his own bathroom. Once all this is over, MC and Beelzebub leave to buy groceries for dinner.
Beelzebub wants to have roast chicken for dinner, and had Satan tell him all the ingredients. He tells the butcher he wants five whole chickens, and says "We're celebrating our first night living together." The butcher misunderstands Beelzebub's meaning, so gives him some relationship advice. The two then run into Mammon and Satan, and all four go to a restaurant Satan says has good pizza. Once there, Satan gushes about the restaurant being a film location for "The Twilight of a Great Family" - a drama TV show he loves.
After eating, MC can either visit bookstores with Satan, or a bakery with Mammon and Beelzebub. If MC goes with Satan, the two get lost in a bookstore and have to find their way out. If MC goes with Mammon and Beelzebub, they use Asmodeus's credit card to pick up a Mont Blanc for Asmodeus, but also buy lots of other food.
After returning to Serenity Manor, they all find Solomon waiting for them with homemade sandwiches and pastries, because Lucifer insisted Solomon make food for them after having to eat his food for lunch. While they eat, Solomon tells MC he thinks it's time they applied for a sorcerer's license, but the food is so bad that MC faints.
MC wakes up in their room, but when they leave it, find themselves in the Demon Lord's Castle. They encounter Little D. No. 2, who informs Barbatos they have arrived. Barbatos tells MC he'd connected their room to the castle earlier because Diavolo would like tea with them. Once everything is set up, Diavolo joins MC by the castle's pond, who tells them it's been quiet and boring since MC and the brothers left. He says Barbatos won't let him visit the Human World until he's made enough progress on his work.
Lucifer texts Diavolo asking for MC to return, as everyone has been waiting for them to make dinner. Leviathan, Beelzebub, and Satan bring MC to the kitchen to ask them about the modern appliances within, like a slow cooker and ice cream maker. They explain that while the Devildom has human world appliances like ovens and blenders, these newer technologies aren't familiar to them. Once dinner is made and everyone digs in, Asmodeus invites MC to a café called The Angel's Halo.
It's morning at Serenity Manor, but only Mammon and MC come out to the living room. It seems everyone else — including Lucifer — is very ill. Not only did Solomon make food for some of the brothers and MC yesterday, but he also left things he made in the manor's fridge, leading to everyone in the house eating his concoctions. Mammon doesn't know why he isn't affected, but he and MC leave to get edible food and medicine.
After picking up some medicine using Lucifer's credit card — which Mammon managed to swipe — the two head to the market and encounter the same butcher MC and Beelzebub spoke to before. Mammon mentions that he and MC also live together, and MC can either claim they don't actually know Mammon, or that he's the one they're "actually serious about."
While waiting in line at a deli, Mammon mentions that he comes to the Human World fairly often, because witches are "always calling him up here." While his only pact is with MC, he says that he can't say no to the witches due to some debts that he has with them. They then overhear two people talking about The Angel's Halo, which is the café Asmodeus wanted to visit. A rumor is going around that if you drink coffee at the café with someone you have a crush on, it'll make them fall in love with you. Mammon then insists they skip the deli and go to the café instead.
When nearly there, the two run into Luke, who is excited to see MC. He brings them into The Angel's Halo, where Simeon explains that he and Luke were appointed by Michael to help coordinate relations between the Human World and Celestial Realm. They'll be living in the Human World for a while, and the café is to help them blend in.
Simeon offer to make some food for them, and Mammon insists on having some of the coffee "everyone's talking about." MC explains the rumor they heard, and Simeon thinks the rumor started when he gave a free cup of coffee to a girl who had a positive development in her love life afterwards.
When MC asks if this is because Simon used his angel powers, he says no, and Luke explains that all angels are born with different powers. They're also assigned ranks depending on how skilled they are at what they do, and Simeon has the rank of archangel. Luke still doesn't have his rank yet, because he's still finding out what he's good at.
Simeon is worried that the rumor will cause Luke and him to blow their cover, so he suggests MC and Mammon pretend to be a couple that has a falling-out after drinking the café's coffee. This idea upsets Mammon, and when practicing, he can't keep up the charade, despite some of his complaints to MC seeming to be genuine.
Back at The Angel's Halo, the café's first day open is a busy one. Mammon and MC are helping Luke and Simeon out by working, as Mammon refused to pretend break-up with MC to fix the rumor issue. Satan and Beelzebub show up as customers as they're both feeling better, and Simeon insists they too help out by working. After the café closes, Luke tell MC that he thinks Simeon has been feeling anxious, but seeing MC seemed to bring relief to him as well as Luke.
Later, when everyone returns to Serenity Manor, Mammon tells Satan what Simeon said about he and Luke coordinating relations between the Human World and Celestial Realm. Satan responds that a job like that should be for angels of the dominion rank, and he thinks Michael really has something else planned in giving that job to Luke and Simeon. Beelzebub then says they should open an umbrella, because there's water leaking from the ceiling. The location it's coming from seems to be Asmodeus's bathroom.
Mammon, Satan, Beelzebub, and MC rush into Asmodeus's bathroom, where they find him unconscious in the bath. After a spell is used to take away his pains, he wakes up feeling dizzy. While the others clean up the water and get him some medicine, MC takes Asmodeus back to bed and tells him about The Angel's Halo, and how it's run by Luke and Simeon. That makes Asmodeus remember that while he was unconscious, he dreamed that he was still an angel in the Celestial Realm. As he talks, MC falls asleep.
MC then opens their eyes to see Asmodeus as an angel, and find themselves in the Celestial Realm. Asmodeus doesn't recognize them, and neither does Beelzebub or Belphegor, who also look like angels. Everyone assumes MC is an angel as well, and Beelzebub tells MC that they're supposed to bring lost angels to Lucifer. Mammon then shows up, saying Lucifer wants to see Beelzebub and Belphegor, and Raphael was looking for Asmodeus with his spear in hand. The brothers all worry now that showing up with MC will get them in even more trouble, so they decide to hide them for now.
MC is brought into the Celestial Palace and to their "secret room," which Leviathan had booby trapped with a bucket of water over the door. After introducing MC to him, Belphegor mentions that Leviathan served as a kind of general before the Celestial Realm was at peace with the Devildom. He now feels like a useless burden to the realm, so MC can suggest he take an interest either in anime or manga from the Human World, both of which he hasn't yet heard of.
Lucifer then enters the room and chastising everyone, so Mammon tries to change the subject to Lucifer being asked by Diavolo to meet with him in the Devildom. Lucifer expresses his displeasure about the meeting, but the subject changes again to how each of the brothers feel like they know MC well despite just meeting.
All of this is interrupted by bright light and a mysterious voice, who explains to MC that they were sent back in time inside of a dream due to eating Solomon's cooking. The voice says that they'll all likely forget what happened, but MC's effect on the brothers will persist. They then wake up back in Asmodeus's room.
Later that night, with still no sign of Leviathan, MC, Mammon, and Beelzebub go to his room again to check on him. After resorting to kicking the door down, they find him perfectly fine playing video games.
At breakfast in Serenity Manor, Lucifer reminds MC that the two of them plus Beelzebub are going to meet Solomon in front of the Sorcerers' Society headquarters. Once there, Solomon explains that the Sorcerers' Society "provides assistance to all of the sorcerers secretly living in the Human World." Also, to become an official sorcerer, one needs a license from the society. Today, their aim is to get a provisional license for MC. Lucifer asks why he and Beelzebub are needed, and Solomon tells them to be patient.
Once inside the building, other sorcerers comment in awe at seeing the two demons, which makes Lucifer realize Solomon's scheme is to make MC look good by bringing them along. Solomon adds that he and the society aren't on the best of terms — despite admitting he and one of his apprentices where the original founders of the society — so MC being his apprentice might make it difficult for them to get in.
The four approach the registration desk, where Solomon asks MC to hold out their hand. The receptionist then presses his staff to the back of MC' hand, and a magic seal of three staves and seven stars — the crest of the Sorcerers' Society — appears. Solomon tells MC that to obtain a full sorcerer's license, they must earn these the seven stars by passing seven trials. For generations, apprentices have always received their first star from their master, so Solomon tells MC to prepare for their first trial.
Solomon binds Lucifer with a spell, which initially makes him furious, but Solomon tells him it's for the sake of MC's first test, so he relents. Solomon then uses another spell to shrink Lucifer down so he can fit in the palm of one's hand, then tells MC their first trial is to keep "mini Lucifer" safe for one full day. They're not allowed to use their pacts on the other brothers, and can only use Beelzebub's powers. Solomon will also stay at Serenity Manor with MC to keep an eye on things.
Before returning home, they stop at The Angel's Halo to see Luke and Simeon, and to come up with a strategy for dealing with the brothers. Beelzebub reminds MC they're allowed to use his powers, but Solomon points out they can't just use the same incantation as before when they used Asmodeus's powers during the retreat at the Demon Lord's Castle. MC will have to understand Beelzebub's "true nature."
As soon as the four set foot inside Serenity Manor, they hear a voice that sounds like Satan's, and they are pulled into a portal that drops them inside of a video game. They find Leviathan dressed as the Lord of Shadow, and he tells MC that they have a mission to defeat "Demon Lord Satan." Beelzebub tries to explain the situation with Lucifer, but Leviathan shows them a projection of Satan, who captured Diavolo after he snuck to the Human World without telling Barbatos, and is using him as a hostage.
With no choice but to save Diavolo, after Leviathan gives them 100 Grimm and a special Lord of Shadow talisman, the party of four head for the town to do some shopping. First they visit the weapon shop, where a merchant that looks just like Little D. No. 2 sells them gear for Solomon and MC, but then they're out of money. The merchant offers them a quest to get his money back from a "greedy monster" at a casino, and he'll give them a discount on armor for Beelzebub if they succeed.
After first ending up at the harbor and going on a "side quest" to defeat the Seven-Headed Sea Serpent — which turns out to be Lotan — the group make it to the inn. They eat supper there, then decide to stay overnight and complete the quest for the armor tomorrow. They can only afford a double room, so MC and Beelzebub take one bed, while Lucifer and Solomon take the other.
Beelzebub tells MC the story of how, when he was still an angel, he wanted to be a soldier, but had trouble controlling his powers. Lucifer then gave him the advice to focus on protecting instead of attacking, which led to Beelzebub becoming a Cherub and guarding the Celestial Realm's gates. That is why he wants to be there whenever Lucifer needs his help.
Morning breaks, and Little D. No. 2 shows MC, Lucifer, Beelzebub, and Solomon to the casino, where they find Mammon. He tries to use a spell to take the miniature Lucifer, but MC is able to call on Beelzebub's power to cancel Mammon's spell and counter it with his own. With Lucifer safe and Mammon defeated, they return to the shop and purchase Beelzebub a Lord of Flies armor set.
The party then travels north to seek "Demon Lord Satan," and after being chased by ghosts in a haunted forest, make their way to a lake protected by a guardian spirit, where they rest for the night. The next day, Lucifer points out that over a days has passed, so Solomon should change him back now. Solomon replies that while it feels like days in the game, it's really only been a few hours.
Beelzebub then spots a treasure chest in the middle of the road containing a warding bottle, medicinal herbs, and a pair of cat ears. The bottle has a talisman attached, and whatever is put inside said bottle is protected from monster attacks. Just as Lucifer is put inside, suddenly, the sky turns to night, and Satan appears. Even if MC chooses to use the cat ears and deal Satan some damage, nothing is enough to stop him from taking Lucifer and leaving Belphegor behind to take care of the others.
Satan promised Belphegor that if he defeated MC and the rest, he could have mini Lucifer to himself for a day. Beelzebub tells MC that before when they fought Mammon he may have been holding back his powers, but now he trusts MC will all that he has. MC uses a spell to channel their power through Beelzebub, who uses powerful winds to slam into Belphegor. Impressed by MC's abilities, Belphegor decides to change sides and join the party.
Because Lucifer was inside the warding bottle when Satan took him, he'll be difficult to mess with, so Solomon considers MC's test as still ongoing. While Satan figures out that he's able to change Lucifer's outfits using magic, there's not much else he can do. Meanwhile, at another inn, Solomon is able to purchase twin rooms for everyone, so the twins stay in one room, while Solomon stays with MC.
The next day, Belphegor uses a spell to teleport the party directly to Satan's castle. Instead of fighting him, MC tells him about his bonds with his brothers — including Lucifer — and that getting along together and being honest about how they feel is more important than earning some star for a sorcerer's license. Beelzebub agrees, and after some affirming words from Lucifer, Satan relents and gives the bottle back to MC. Everyone thinks it's now over, but Solomon then states that he is actually the final boss.
Solomon tells MC they still haven't fully used all of Beelzebub's powers, so if the trial ended here, they'd fail. He summons Asmodeus and uses his powers to increase Asmodeus's strength. However, MC is finally able to draw out all of Beelzebub's powers as well, and the battle is won. Everyone then returns to Serenity Manor, and Lucifer is restored to his proper size. MC also earned their first star, which now faintly glows in the magical seal on their hand.
Meanwhile, Mammon, Leviathan, Satan, and Asmodeus are subjected to Solomon's cooking as punishment. Belphegor managed to slip away, but while Beelzebub and MC are talking, he wonders out loud if they had forgotten about something...
Later, Lucifer and MC meet with Diavolo at the Demon Lord's Castle to apologize for leaving him behind in the game. While they did later go back and get him, and Diavolo is all smiles, he's still very angry about being forgotten. MC can either suggest Lucifer meows like a cat when apologizing, or tell Diavolo that Lucifer agrees to do anything he asks as an apology.
Leviathan, Belphegor, and MC visit The Angel's Halo and tell Simeon about how they forgot Diavolo in the Devil's Quest game, so they had to go back and get him. Lucifer then helped Diavolo catch up with his work as an apology, so he's now able to come to Serenity Manor and visit that day. Leviathan comments that he'll spend the day in his room, as he's "not the biggest fan" of Diavolo, and is also worried about making Lucifer mad if he says or does something he shouldn't. Simeon then gets a call from Lucifer, who tells him MC and his brothers need to get home right away, because Diavolo is missing.
Back at the manor, Lucifer is pacing back and forth while on the phone with Barbatos trying to find out where Diavolo went. Asmodeus explains that when Barbatos — who has a case of demonic flu — opened a portal for Diavolo to the Human World, he sneezed, meaning while the portal did lead to the Human World, no one knows exactly where. Leviathan says he knows someone who might know where Diavolo is, so they all head to his room.
Leviathan introduces them all to his friend "Crowe," which is actually a voice-activated smart speaker. Leviathan says that Crow knows everything, so the brothers spend time asking it questions and ignoring MC's explanation that Crowe is just a piece of technology. MC resorts to using their pacts to get everyone's attention, and after explaining what a smart speaker is, Leviathan refuses to accept their explanation.
Leviathan then asks Crowe to find Diavolo, and after providing Diavolo's phone number, Crowe sends the location information to Leviathan's D.D.D.. The brothers and MC rush to the location to find Diavolo in a karaoke parlor. A note written in Devildom script on the door to the exit says the room is cursed, and the only way out is to score a perfect 100 when singing karaoke.
Diavolo mentions that the karaoke parlor is owned by the Three-Legged Crow Group, the company that also developed the D.D.D. and who recently have expanded into the Human World market. They are also developing a smart speaker, which he says there's a prototype for at Serenity Manor. Leviathan is devastated to realize his "friend" is just some technology, and feels even worse when the voice of "Crowe" comes from the karaoke machine and tells them to get ready.
Crowe explains that the rules are to take turns singing one song, and a score will be given after the performance. If anyone gets 100, the group wins, but there will also be "surprises" to keep the game interesting. Asmodeus sings a song first, but hears the imaginary voices of his fans in the middle of the song, causing him to mess up and only score an 88. He then disappears, having been sent by Crowe to the "punishment room."
Mammon goes next, but realizes too late that he chose to sing a romance song in front of MC, and fails to start singing in time due to embarrassment. He too is then sent to the punishment room. Diavolo offers to sing next, but Lucifer refuses the idea, saying that as the future demon king, he's too important to the Devildom to take the risk. While Beelzebub is busy ordering food from Crowe, Diavolo suggests he and Belphegor sing a duet together. However, in the middle of the song, Beelzebub's food arrives. When he stops singing to eat it, both twins are sent to the punishment room.
Satan and then Diavolo ask for Leviathan to sing next, but he doesn't want to sing in front of Diavolo, so instead Satan sings next. Mid-song, the screen displaying the lyrics starts showing cat videos, and as expected, Satan ends up failing his song as well.
Diavolo comments that he's often asked Lucifer to go sing karaoke with him, with Lucifer always refusing, so he's ecstatic that he gets to hear Lucifer sing now. Before he even starts, however, he disappears. Crowe claims to have "pushed the erase button by accident," which leaves only MC, Leviathan, and Diavolo left.
Diavolo again tries to sing next, saying he can't ask MC or Leviathan to sing for him, and Leviathan replies that this is what he can't stand about Diavolo. He goes on to say Diavolo is "always completely just and completely fair" and "never does anything bad," which just makes Leviathan hate himself more, because he isn't like that.
Diavolo responds that Leviathan's humility is one of his best qualities, then brings up times in the past when things only went well due to his help. With both Diavolo and MC's positive words, Leviathan tries to sing the next song, but Crowe says that time is up and automatically chooses a song for Diavolo to sing. Diavolo sings the song, but even after getting a score of 100, he's still sent to a cramped, pitch-black room, which is the "punishment room" everyone else has also been sent to.
Crowe announces that Diavolo scoring 100 means Leviathan and MC are allowed to leave, but Leviathan tells Crowe he's going to sing, and if he scores 100, Crowe has to bring everyone else back. MC can either sing a duet with Leviathan, or let him sing alone, but either way, he too scores a 100, and everyone returns to Serenity Manor.
MC finds Leviathan in his room, who confesses to MC that he worries that someday someone better than him will show up and take MC away from him. Diavolo then sends MC a text asking to see MC before he goes, and Leviathan after joking about telling Crowe to trap them both in his room together, he says it's okay for MC to go.
MC meets Diavolo outside by the pool, who admits to MC that the karaoke incident was his fault. After spending time with all of the brothers gone from the Devildom, his memories of what it was like before they arrived made him lonely, so when he learned the karaoke parlor was owned by Three-Legged Crow Group, he couldn't help wanting to enjoy having fun with everyone.
MC has the choice to either forgive him or not, then Barbatos appears, still sneezing and running a fever. He apologizes to Diavolo for his portal sending him to the wrong place, and apologizes to MC and Lucifer as well, who was standing aside waiting on MC. Diavolo and Barbatos leave, then Lucifer and MC head inside to find the common room flooded, as Leviathan had summoned Lotan after his brothers teased him.
The next morning, Satan turns on the TV to see Diavolo and Barbatos on a news program about Corvo Lagoon View, the eighth hotel to be opened by the Corvo hotel chain, and a chain also owned by the Three-Legged Crow Group. Diavolo and Barbatos then arrive in the common room, where Diavolo tells everyone he now gets to stay in the Human World. He also stopped by because he hadn't been able to tell MC what he wanted last night. He uses his magic to give MC the second star of the Sorcerers' Society magic seal.
Afterwards, Barbatos visits The Angel's Halo, where Simeon and Luke had been trying — and failing — to give Solomon cooking lessons to make his food less terrible. Barbatos asks Simeon why Solomon had recently started coming to him and asking him to try his cooking. He also tells Simeon that Solomon's food is likely what gave him the flu that led to him sending Diavolo to the karaoke parlor. Luke advises Simeon to start apologizing to a clearly angry Barbatos.
Mammon, Luke, and MC arrive at Hotel Corvo and they all marvel at it. Luke complains that he doesn't like how Devildom corporations are starting to inroad into the Human World. Barbatos appears, and reassures him that Lord Diavolo's intentions are purely peaceful, should he inform Michael. Then Mammon teases Luke for being a tattletale.
Once inside the hotel, Barbatos talks about how Leviathan and Diavolo have become close since the earlier karaoke incident, and even play online games together all night. Mammon then remarks on Barbatos's odd fashion choice, and Barbatos tells him that his cover story while in the Human world is that her works as an importer of tea leaves, and hopes his outfit conveys this.
A bit later, Barbatos brews them all fairy ring tea. He explains on rare occasions, golden-hued flowers grow in these rings. MC can ask about the fairies, but they all explain fairies have gone extinct in the Human World.
Mammon is quite displeased that they are extinct, but then Barbatos mentions they actually might not all be gone. They might be hiding in secret in the Human World, and the flower fairy rings that are created from them make rare treats. This makes Luke, Mammon, and MC decide to go on a quest to find fairy rings. Mammon suggests they look for clues in a library.
In the library, they split up, and MC can either go with Mammon or Luke. If MC chooses Mammon, they learn about the time he was an angel. If MC goes with Luke, he teaches MC more about Michael. They ended up not finding anything but rumors. Mammon at one point insults the image of Micheal, and Luke becomes incredibly defensive of the archangel. While trying to calm Luke down, Solomon appears.
After explaining what their plans are to Solomon, he tells them they won't find the information they're looking for in human literature. Instead, they should seek places free from human influence to find the fairies themselves. Luke suddenly exclaims he has a plan to find the fairies, and takes them to Levi's room. Once there, he asks Crowe for help. Crowe says that faeries can be found in the area of Lake lo Lanthe.
Meanwhile, Asmodeus, Barbatos, and Solomon meet each other in the Hotel. Asmo is happy all three are alone together, because the last time was during Solomon's dispute with the Sorcerers' Society. Then Barbatos and Solomon reminisce about the past, and when Solomon made a pact with him. Afterwards, Solomon reveals he wants to make MC into a full-fledged sorcerer.
Luke finds Simeon to ask him for permission to travel on the overnight train to the Lake lo Lanthe, and Simeon agrees. Luke also promises to look for somebody to help take care of The Angel's Halo. They think of all the demon brothers, but asking most of them would not be a good idea. In the end, they decide to ask Satan. Initially, Satan declines, but MC ends up persuading him to work anyways.
Mammon and MC return to Serenity Manor, because they want to ask Lucifer for permission to go to the lake, but the brothers tell them he's still out with Lord Diavolo. They talk a little about the fairy hunt, and Belphegor doubts Mammon's ability to handle it. Lucifer then returns, and they ask the big question. Lucifer agrees, but also refuses to pay for their excursion. Then MC asks for a game of cards, and if they win, he will pay.
After the game, MC ends up in Mammon's room with him, and they take turns asking Crowe questions, but suddenly they hear an unknown person screaming.
MC and Solomon are in a park in the Human World, where Solomon is teaching MC a teleportation spell. After a successful attempt, Solomon announces that MC should now be able to teleport between worlds. He then gets an urgent phone call, and tells MC he has to leave.
A letter then appears from nowhere and lands in MC's hand. They open it to see Diavolo in the student council room, who explains the letter was magic and makes it seem like Diavolo's actually there. The seven brothers are there as well, and they all insist on speaking to MC too. After an argument breaks out, Diavolo is able to tell MC that he has something important he wants to discuss with them, and would like them to come to the Devildom as soon as possible.
After a text from Solomon — who somehow knew MC was about to teleport to the Devildom — MC teleports to the RAD library and lands on top of Satan. He takes MC to speak with Diavolo, but they run into Asmodeus on the way, who says he has something to show MC.
Asmodeus takes MC to an empty classroom, and shows him a nail polish he designed himself. The multicolored polish is made with water from the Phantom Spring, but when applied, it turns transparent, as it does after Asmodeus paints MC's nails. Beelzebub and Belphegor then find them, and Asmodeus paints their nails with his new polish as well.
Beelzebub then takes Asmodeus to see Lucifer, while Belphegor stays with MC. After his stomach starts growing, the two get some bread to eat, but even after that, Belphegor doesn't feel full. They head out to the courtyard when they suddenly hear Asmodeus yell, and find him being crushed under a sleeping Beelzebub. They help him out, then MC stays with Beelzebub while Asmodeus and Belphegor go find help for carrying him.
After waking Beelzebub up, he explains he suddenly felt sleepy, but now that he's awake, they can go to the council room together. Once there, MC finds that everyone prepared a surprise celebration for their return to the Devildom. After Lucifer hands MC a glass of Demonus, Asmodeus mentions that there are going to be new exchange students at RAD. Diavolo interrupts him before he can give names, and proposes a toast.
Mammon tells MC to hurry and eat some of Barbatos's desserts before Beelzebub eats them all, but notices instead it's Belphegor eating everything he can, while Beelzebub says he isn't hungry, and is tired instead. Meanwhile, Diavolo pours MC some more Demonus, and tells them he'll call a council meeting to talk with MC and the others later.
Once the party's over, Asmodeus asks where MC will be staying while in the Devildom. Diavolo answers the Demon Lord's Castle, and points out that MC isn't an exchange student for this visit. However, the brothers argue that MC should stay at the House of Lamentation.
Mammon, Leviathan, and Asmodeus return to the House of Lamentation with MC. After arguing about who gets to do what with MC first now that they're back, MC spots an antique box in the living room. Inside are the letters that MC wrote to everyone while they were in the Human World.
Satan, Beelzebub, and Belphegor then return from cleaning up after the party, with Belphegor still eating and Beelzebub tired and yawning. Later, however, the twins join MC and the others playing cards in MC's room, and both seem to be back to normal. Belphegor is tired again, and Beelzebub brought an armful of food with him. Everyone but Satan and Lucifer spent the night in MC's room, and the next morning Asmodeus paints Mammon and Leviathan's nails with his new nail polish while they're still sleeping.
At RAD later in the day, Leviathan is spending time using his D.D.D. for gambling, while Mammon is playing an anime dating game. Beelzebub, Belphegor, and MC bring Leviathan out into the hallway to ask why he's behaving so oddly, but he just leaves to go gambling at a racetrack. The three then get Lucifer and Satan, and they all try to talk to Mammon, who starts talking negatively about himself as Leviathan always does.
After realizing Asmodeus's nail polish is the likely culprit, and the twins say they stopped acting strange after they both showered, MC finds Mammon in the Colosseum and uses magic to douse him in water. He then returns to normal, and so does Leviathan after MC does the same to him.
Once all this is settled, the student council meetings begins with Diavolo telling MC he's been thinking about before, when the brothers asked him about MC joining their family before they had to leave the Human World. He thinks the idea is worth a shot, and asks MC to once again stay in the Devildom as an exchange student. The last exchange program was only meant to provide cultural exchanges among inhabitants of all three worlds. This time, the goal is to "make a stronger case for mutual understanding."
Diavolo also asks MC if they would like to be an officer on the student council. Having MC as part of the student council would make it clear how close MC is to everyone, and how much everyone trusts each other. To become an officer, however, tradition dictates that MC must undergo a trial, and not an easy one. Naturally, MC accepts the challenge anyway.
Later, Mammon proposes to use Asmodeus's nail polish on Satan and Lucifer so they swap personalities. They paint Satan's nails while he's sleeping in the music room, then surprisingly, Lucifer lets MC paint his nails as well. Even after Satan wakes up, however, no one can spot any differences in the two's personalities.