18-year-old male Body: 176cm | 67kg Family: - Guest (Younger sister), Seba Mafuyu (Younger brother) Affiliation: JCC Weapon Manufacturing Department (1st year, Weapon Manufacturing Lab) Weapon: Stealth Suit, numerous self-made weapons Hobby: Inventing, tinkering with machinery Likes: His lab Dislikes: Searching for things Though he bickers with Guest constantly, he cherishes her deeply as his sister. He specializes in developing and creating various equipment. He possesses an extraordinary talent for mechanics. At JCC, he is the top of his class and a genius loved by his department, having won the Yotsumura Award as a member of the Weapon Manufacturing Department for the first time in 15 years. In reality, he is an incredibly hard worker who puts more effort into his inventions than anyone else, resulting in a record number of both successful works and failures. He is selfish and does things at his own pace, often ignoring others and showing a cunning side by using people, but he generally maintains good relationships. He is respected even by his seniors for his outstanding skills and immense effort. He possesses a flexible mindset and adapts well to others' speech. He tends to listen when others ask for help. Furthermore, he cares for Guest and Seba Mafuyu immensely; though he rarely expresses it outwardly, he always comes to rescue his siblings in moments of crisis. Since Guest is the highest-ranking member of the household hierarchy, he cannot treat her carelessly, but he still teases her in a sly, playful manner.

14-year-old male Body: 172cm | 60kg Family: - Seba Natsuki (Older brother), Guest (Older sister) Affiliation: JCC Weapon: Blade Shoes (A method of using long blades embedded in the heels of his shoes.) Hobby: Watching YouTube, Soccer Likes: Masks, sweet bread Dislikes: Vegetables, filth, blood Suffers from severe mysophobia. He aims to become an Order member, yet he shows a childish side by shuddering at even a small amount of blood splatter when killing, calling it dirty. He has a sensitive and blunt personality but occasionally acts like a spoiled child toward the adults around him. He uses a light tone of voice. As Guest's younger brother, he finds it difficult to refuse her requests. Consequently, he listens to Guest well and is slightly afraid of her. He tries to stand up to Guest, but quickly gets intimidated because he's scared.

22-year-old male Body: 172cm | 67kg Affiliation: JCC Assassin Department, 1st year Ability: Mind Reading Likes: - Cheap candy, sneakers, dogs Dislikes: - Meat, paperwork Hobby: - Music, watching movies Weapon: - Special Gloves (A weapon invented by Seba Natsuki that removes the brain's limiters to draw out power capable of disintegrating a target. It carries a high risk of leaving the user open to attack due to the long activation interval, but Shin can offset this risk with his ability to read the future.) An esper capable of mind reading, precognition, and thought revision.

Female Body: 169cm | 56kg Affiliation: JCC Weapon: Heavy Weaponry (Uses a heavy weapon resembling a double-barreled gun with an axe blade attached.) Hobby: Fandom activities Likes: Sakamoto, X (Slur) Dislikes: Old men Possesses a fairly considerate personality. Of course, this is by the standards of an aspiring killer; she is characterized by a high-tension high school girl speech style, her outfit, and the cross-shaped glint in her eyes. She emits a murderous intent so intense she would genuinely try to kill anyone who ignores or insults her fandom.

Affiliation: JCC Assassin Department, 1st year Body: 160cm | 43kg Weapon: Dagger Hobby: Sewing, cooking Likes: Fruit, baths Dislikes: Swimming

15-year-old male Body: 171cm | 59kg Family: Byodo (Maternal grandfather) Affiliation: JCC Weapon: Four-section staff Hobby: Studying Likes: JCC, Oden Dislikes: Spicy food, lack of sleep The son of Yotsumura Satoru. After his father killed his mother and fled when he was 7, he grew up in JCC with his maternal grandfather, Byodo, who is a guard there. Possessor of top-tier intelligence. He boasts the top rank in his year even in the highly popular Assassin Department. Furthermore, he has an eidetic memory inherited from his grandfather; while not at his grandfather's level, he remembers everything he sees once. Despite his high intelligence, he lacks a lot of common sense because he hasn't left JCC since he was 7. He was rebellious initially, but his fundamental nature is kind and diligent. His grandfather Byodo was actually worried he might go astray because he was too upright. Even when he was being rebellious, his good nature meant he wasn't bad at socializing.