The Main Character (MC) is one of the only two human exchange students attending RAD. Their default name is Yuki, however, the player can change this name alongside their birth-date at the start of the game.
MC's personality is determined by the responses and actions they make during the main story, Event stories, chats, and calls.
However, due to the machinations of the game, MC is often considered nosy due to their tendency to get into matters that, at face value, appear to have nothing to do with them. This trait is often viewed as a detriment by other characters.
Mammon once lamented, during Lesson 16-A, that MC "may seem like someone who's really got it together", but has a "boneheaded streak", and that they can be "weak, and super reckless...and too damn gutsy". The recklessness is later confirmed, as they frequently choose to head toward danger rather than away from it.
In the Devilgram story "Three Wishes", MC is shown to be very selfless for their wishes was to give the brothers an extravagant dinner to thank them and free Belphegor from the lamp, thus forfeiting their third wish.
They have a tendency to be too overzealous when they enforce the pacts on the brothers.
According Simeon, their greatest strength is being flexible and being able to adapt to almost any situation.
The majority of MC's background remains unknown, with the only backstory being that they were picked randomly by Lucifer to be part of the exchange program at RAD. Apparently, they also had no knowledge of being chosen, for they were confused at appearing suddenly at the Devildom's student council hall. However, it could be very possible that Barbatos influenced in some way the choice due to his ability to foresee the future and the different versions of the timeline.
Initially portrayed as the disembodied voice MC occasionally hears, Lilith is later revealed to be their distant ancestor. She also reveals that she specifically chose MC to influence and encourage in order to fix the familial problems of the demon brothers - in particular, the rift between Belphegor and Lucifer, and also brought their photo to Lucifer's attention making him choose them for the exchange program.
- This is the first Shall We Date game where the MC isn't exclusively female. Depending on the player, MC may be any gender, and is identified using they/them pronouns.
- Although MC's physical appearance completely depends on the player, the demon brothers have noted that they are kind of cute and hard to dislike.
- Asmodeus does provide a few features of MC, such as their ring fingers being longer than their index fingers, and their ears being on the small side.
- On the back of MC's hand, there's a tattoo of three staves and seven stars, which symbolizes the Sorcerer's Society. According to Solomon, the stars represent the seven virtues: temperance, gratitude, chastity, humility, generosity, patience, and diligence.
- In the TSL series, the human protagonist, Henry, is correlated to MC.
- MC's icon is a sheep, and they are depicted as a sheep plush in the upcoming anime, as shown in the promotional sneak peek.
- The sheep often symbolizes humans in the Bible as followers of God, and were considered pure and innocent.
- MC has so far developed kemonomini traits three seperate times.
- The first is in We're All Bad Here, where they developed bunny ears after eating one of Simeon's cookies.
- The second is when MC has the choice of being a dog or rabbit as a game avatar in the Devilgram Animal Game.
- The third is in Lesson 53, when MC is magically given a sheep's tail to play the game Tail Thieves.
- They and Leviathan are the only ones who don't use their personal photo. MC does not have one because the developers wanted MC to be based on their players.
- Despite Lilith being their ancestor, MC isn't related to any of the brothers. This is both because Lilith was reincarnated as a human, and because as created angels the brothers are not blood-related to begin with.
- In the chat A Question from Beel, Beelzebub will ask MC if they have any brothers, which the player can reply yes or no.
- If answering yes, MC has likely more than one brother.
- Asmodeus and Mammon are the only brothers to not have transformed into their demon form in a fit of rage against MC.
- In the first draft of the game, MC was originally going to be in high school employed to babysit the seven brothers (under the guise of humans) at the House of Lamentation in the human world (which would be set in the English countryside)
- They wouldn't have discovered the demon's true identities until the second half of the story. 
- At the time, they were also written in mind as female.
- MC also would have had a mother who's an artist, and one of her art pieces was in Diavolo's possession. 
- In Lesson 41, this plot was reused as a cover concocted by the brothers (mostly by Mammon and Asmodeus) to surprise MC when they were staying in the human realm during their vacation.
- MC appears in the Another Cat Person card as a cat.
- This is the first time MC has appeared on any card.
- In Lesson 4-15, Lucifer commented that MC seems to be "the type of person that has trouble lying."
- It is hinted in Lesson 4-A (Normal) that MC might have a sweet tooth, considering how Mammon finds a container filled with cookies and chocolate in their room.
- In Lesson 5-7 (Normal), it is revealed that MC's room is right behind the kitchen. A large part of their room was also destroyed after Beelzebub destroys the kitchen wall connected to their room.
- In Lesson 17-7, it is implied that MC does well at card games. There is an option to downplay it, but Belphegor will believe they are only saying that because they felt sorry for him.
- The order of the demon brothers who made pacts with MC from first to last goes as follows: Mammon (Lesson 2-8), Leviathan (Lesson 4-6), Beelzebub (Lesson 6-10), Asmodeus (Lesson 8-15), Satan (Lesson 12-10), Belphegor (Lesson 18-19), and finally Lucifer (Lesson 20-14).
- In Lesson 41-16 (Hard), the brothers compare MC to the lead character in a horror movie. This is becase they place the safety of others above their own (regardless of the consequences), spend a lot of energy trying to fix their friends' problems, and are very kind and sweet.