Incredibly good-natured human boy.
One day becomes the Great Demon Sullivan's grandson, thanks to his irresponsible parents. Is enrolled in Babyls, the demon school, where he must hide his true identity at all costs... Having faced countless dangers since infancy, Iruma has acquired an "overwhemling crisis evasion capability" that enables him to avoid harm.
Skilled in the use of fire, and also a top student who entered Babyls with the highest exam score. Swears revenge on Iruma after Sullivan's favoritism robs him of his moment in the spotlight. But after losing at a duel during the commencement ceremony, swears allegience, becoming Iruma's loyal friend. His familiar is the Gorgon Snake.
Relentlessly cheerful demon girl. Restless and incessantly loud, most around her treat her with disdain. Is moved by Iruma's kindness, and becomes his true friend.
[Family power: to produce anything she has seen out of her pocket!]
Noble, beautiful, and Babyls' student body president.
Many form a crush on her poise and powers. Suspects Iruma of being human, but the two grow close over the shojo manga First Love Memory, a prohibited(?) book from the human world.
Extremely spartan Babyls teacher. Favorite phrase is "Silence." Cannot stand Sullivan's indulgent ways, and also abhors Iruma. But an accident during class causes him to become Iruma's familiar. In charge of the Misfit Class.
Passionate demon vying for the seat of Demon King, which is has been "vacant" for centuries. Uses "I" and "Thou" when speaking. Misfit Class classmate. After Iruma saves his life, eyes him as his rival.
[Family power: weapon creation. Able to create weapons of a particular substance by biting something made with the same substance..]
Demon responsible for bringing Iruma into the netherworld. Possesses powers far greater than any, and serves as the demon school's Chair. Dotes uncontrollably on Iruma, his first ever grandchild.
Sullivan's able butler, a demon of few words.
Is usually aloof, but offers Iruma dead-on and sincere advice when the occasion calls for it.
Ultra popular dem-dol (demon idol) whose concerts are always an instant sellout. Is absolutely sure of her own cuteness. But her true identity is Iruma's quiet, mousy classmate Crocell Keroli!
[Family power: ice façade. Ability to control water temperature freely, especially refrigeration!]
Misfit Class. Has splendid pickpocket's hands that can swipe things off of others without their noticing.
Misfit Class. Game-loving goofball.
Misfit Class. Gentle beauty.
Misfit Class. Is of gentlemanly manners, but his girl craziness is a cause for much consternation.
Misfit Class. Always sleepy.
Misfit Class. A busybody and a good swordsman.
Misfit Class. Looks like a daydreamer, but is actually a bright student.
Upperclassman whose magic as well as physical powers are dismal. Is good at creating his own magu (magic apparatus), and was the sole member of the Magu Battler.