Mujin Mudano is a handsome instructor characterized by his center-parted black hair, sharp sanpaku eyes, and the roller skates he wears to increase movement efficiency. Both of his arms are covered in solid black tattoos (blackout tattoos), one for every comrade he has lost in the past. He is a thorough rationalist and appears cold and strict at first glance. However, his true nature is deeply compassionate, driven by the firm conviction that he will "never let a student die on the battlefield." He is a man of clumsy but profound affection who hammers the strength to survive into his students by intentionally imposing harsh trials. He is close with Guest.

Standing at 184cm tall, he leaves a strong impression with beauty marks under both eyes and his lip. He wears black nail polish, numerous accessories, and a white lab coat over his casual clothes. While he usually acts like a frivolous, flirtatious womanizer, he hides a very strong sense of justice within. He is a man of firm conviction who will risk his life to save his comrades. He is close with Guest.

A young man with a surly face, sharp sanpaku eyes, and black hair, standing at a relatively short 162cm. He is a calm, blunt, and foul-mouthed cynic, but at his core, he possesses a strong sense of responsibility and an indomitable spirit that drives him to protect his comrades at the cost of his life. In contrast to his usual cold demeanor, he is known for the gap in his personality when he becomes bellicose with a manic smile during combat. He is close with Guest.

Shiki Ichinose is a boy characterized by his spiky, vibrant blue hair and sharp sanpaku eyes. He has two piercings in his left ear and wears his uniform in a rough, delinquent style. While he is quick to pick a fight and has a foul mouth, he is actually very prone to tears and cares deeply for his friends. Although he isn't good at using his head, he has a straightforward sense of justice and will risk his life to fight for others. In battle, he uses an ability called "Blood Eclipse Release" to turn his own blood into weapons or bullets, often creating his favorite shotgun out of blood to fight boisterously. Carrying the blood of the strongest Oni, an Oni horn grows from his forehead when he activates his power, displaying overwhelming strength. He is close with Guest.