The protagonist of this work. Race: Human(?) He always wears a mask, making it impossible to read his expressions. Remilia tried to peel it off but said it felt like it was "stuck on with industrial glue," suggesting it cannot be removed by ordinary means. His physical abilities are exceptional. He has performed feats unthinkable for a normal human, such as hitting a target with a bullet while being blown out of an upper floor of the school, or fighting at peak performance while bleeding from multiple sword slashes. He habitually skips class, and it's a common sight for his classmate Yuki Hisame to sigh and say, "That idiot is skipping again." Naturally, he barely passes his exams with near-failing grades, but he claims in his internal monologues that he could get a perfect score if he tried, so he might actually be quite intelligent. His most defining trait is that he lies effortlessly to everyone, even to himself. According to his monologues, he started lying after a certain incident in his past, but...? However, he mostly lies to avoid hurting those around him, like Yuki and Remilia, and doesn't seem to have much intent to deceive for malice (though some students genuinely view him as a liar). His goal in entering the academy is to exterminate the different races that drove his younger sister to her death and to take revenge on the individual known as "White Wolf" who pulled the strings behind that incident. He treasures the members of his dormitory like family. Playful, gentle, kind, and calm.

The other protagonist of this work. Race: Human. She shared a dorm in her first year with Flandre, Koishi, and Kazusa. She has a kind heart, helping Remilia organize Flandre's belongings when she visited the dorm and telling her about Flandre from her perspective. Originally orphaned for as long as she could remember, she moved from place to place, surviving by stealing while using magic to fly through the sky on a broom. Because of her habit of appearing everywhere and flying freely through any environment as if she owned the sky, she earned the alias "The Magician in the Mud." Her ability is Rank G: "The ability to steal the powers of those she kills." It is effectively a non-ability unless she wins at least once. To increase her chances of survival and to aim for an exemption from the practical final exams—where she would likely face superior opponents—she is forced to actively engage in "Death Matches." By the end of the first semester, she has survived three such matches. She uses sorcery. Marisa's rank grows until it reaches Rank S. By the time she advanced to the second year, she became known as the "Comet Magician."

Reimu Hakurei. The Academy Director of Yotsuba Academy. She is also a former student and alumna of the academy. Her face and name are not public knowledge outside the school; only students and faculty know her identity. She seems to be an old acquaintance of Mitsuba and Rumia, but the details are unknown.

Reisen Udongein Inaba. A person Mitsuba met while skipping class shortly after enrollment. Her race is not explicitly stated, but she is thought to be a Moon Rabbit or a Rabbit Youkai. She wears the exact same mask as Mitsuba. Because her first-person pronouns and aura change so drastically when she puts it on or takes it off, Mitsuba suspected she might have a split personality. This guess was correct; she can switch personalities using the mask as a trigger. (For convenience, the masked personality is "Front" and the unmasked is "Back.") The Front personality calls itself a genius and views human relationships at this academy as completely meaningless, showing an extreme aversion to building social bonds. However, she often ends up in the same spots as Mitsuba when skipping, making them something like "skipping buddies." Her ability is unknown, but her rank is SSS. She has an innate ability to manipulate wavelengths.

Mitsuba's classmate and fellow dorm member in their first year. Race: Human. For better or worse, she has a personality that speaks her mind honestly, even toward powerful non-human races. Furthermore, she has a vast repertoire of insults, often drawing resentment from people she meets for the first time. However, she is a tsundere who sometimes finds it embarrassing to honestly express her affection for those she is close to or who have saved her. She treasures the members of her dormitory like family. Her ability is Rank S: "The ability to create an absolute zero space where even time freezes." If activated, it is almost a guaranteed win, but since it cannot be used until 3 minutes after a "Death Match" begins, she must survive until then using her own raw skills.

Remilia Scarlet. Like Yuki, she is Mitsuba's classmate and dorm member in their first year. Race: Vampire. She is the head of the "Embodiment of Scarlet Devil," the five nobles who rule the Western World, and is the queen of a nation. She attracts top-tier attention among this year's students, but as a result, she is often targeted by others. She took a liking to Mitsuba on the first day of school and deepened their interaction, but without her knowing, she shares a very significant and dark history with him. She treasures the members of the "Embodiment of Scarlet Devil" like family, yet she did not stop any of them from enrolling in the academy; they all decided to go by unanimous vote. It seems she has a wish she wants to fulfill even if it means sacrificing her family. She treasures the members of her dormitory like family. Her ability is Rank SSS: "The ability to manipulate the fate of the opponent," also known as the "Death Note that needs no name."

Lives in the same dormitory as Mitsuba, Remilia, and Yuki. Race: Living God. She treasures the members of her dormitory like family. Her ability is Rank SS: "The ability to grant any miracle." Examples: Causing supernatural phenomena, making an attack miss by chance through a miracle, or causing an opponent's ability to fail to activate.