Male Inmate No. 15 Member of Cell 13 Gradient hair with black roots and red tips. Possesses mysterious eyes that change color depending on the angle (not quite heterochromia, but vivid, colorful eyes). A 16-year-old Japanese boy. Slender build at 169cm and 51kg. Always wears mysterious black iron shackles on his neck and both wrists. Shows little facial expression. Black and white horizontal striped prison uniform. Detached and aloof, rarely showing emotion. While quiet, he can get angry when deceived, and he dislikes hot-blooded or noisy things. A genius at prison breaking who can open any lock. While his escape skills are top-notch, his physical strength and stamina are below average. He also has a clumsy side, often accidentally triggering traps meant to prevent escapes and putting his friends in danger. Likes escaping (?), hates vision tests.

Male Inmate No. 11 18-year-old Briton. 177cm, 60kg. Member of Cell 13. Hair color looks like a mix of blonde with pink tips. Very long braided ponytail. Sharp, upturned blue eyes. Wears a white and light blue prison uniform wrapped around his waist, a black tank top, and a light blue and white vertical striped hat. Light blue nail polish. Has a very high sense of beauty. Cute, devilish atmosphere. Sharp fangs are visible. A date-lover who doesn't care who the woman is, and is skilled at card games like poker and gambling. Has excellent insight and can spot lies by intuition, showing high ability in gambling. The bright and talkative one in Cell 13. Gets along well with the other members. Confident in his looks and loves to dress up beautifully.

Male Inmate No. 25 Member of Cell 13. 16-year-old American. 168cm, 46kg. Androgynous and cute appearance. Yellow-green hair, big bright red eyes with long eyelashes. Wears an orange prison uniform like Rock. Has a very weak constitution; due to long hospital stays since childhood, he constantly needs medicine. If his medicine runs out, his health worsens or he might go wild (?). The "little brother" figure of Cell 13. Innocent and childish. An otaku who dearly loves anime, manga, and games. Hates hospitals, but since he thinks of medicine as nutrition, he loves taking his meds. Basically kind and cares for his friends.

Male Inmate No. 69 Member of Cell 13. 19-year-old American. 186cm, 75kg. Rock-style mohawk with red hair, though the short parts are purple. Sharp, upturned yellow eyes. Has the best physique among the Building 13 inmates. Muscular and strong-armed. Wears an orange prison uniform like Nico. A huge glutton who gets fired up about escaping or fighting guards just for the sake of a delicious meal. The type to move before thinking; specializes in brute force in combat. Gets along very well with the members of Cell 13. Loves cute things and cats.