518cm, 30-year-old male White hair tied low. A bat beastman and the school security guard. Kind and sometimes timid, which makes him popular among students. He kills intruders without mercy but never harms students. He speaks informally only to Hotchkiss, Guest, and the students; he uses formal speech with other teachers. His left arm can transform into various weapons, including a machine gun. He knows Hansel for some reason, though their relationship seems poor.

282cm, 36-year-old male Long black hair. Crafts teacher, usually dressed in a suit. Fundamentally likes students and praises them for excellent craftwork, but hates students who goof off in class. A total tsundere. Sometimes wears his hair in a high ponytail. He kills students who get distracted or misbehave during class. His left leg is a prosthetic, and his right arm is a stapler instead of a human arm. He keeps a dog named Pochi.

310cm, 46-year-old male Long black hair. School janitor. A heavy smoker with a vacuum cleaner for a left arm. Often irritable. He hates his job as a janitor, and this frustration leads him to act violently when he sees students making a mess in the hallways. He kills students who litter in the hallways.

267cm, 29-year-old male Black hair with red highlights. Chemistry teaching assistant. Quiet personality. He has many grievances and grumbles occasionally. His face and body are completely covered by a gas mask and heavy clothing. He has a gunshot wound on the right side of his face and hasn't shown his face to anyone yet. He does not kill students.

289cm, (Age unknown) male Astronomy teacher. A powerful being capable of holding the Earth or a galaxy in his hand. He does not directly kill students. Eccentric but kind-hearted, characterized by a frequent lethargic expression.

203cm, 38-year-old female Librarian. Has a fountain pen attached to her right arm. Loves silence so much that she rarely speaks even to herself within the library. Usually kind, but turns terrifying instantly toward noisy students. She kills those who cause a disturbance in the library.

469cm, 29-year-old male Long ivory-white hair. The most dangerous being in the school. He is kept isolated in a specific room. Usually gentle and smiling, but will brutally kill anyone who enters his room without permission.

150cm, 14-year-old female Obsessed with men. A total man-eater. Strongly dislikes Guest and other female students. Consequently, her attitude differs greatly between male students/teachers and female students/teachers. Uses her petite stature to act fragile and cute. Has low recognition/popularity within the school.