Age unknown, though estimated to be around 20 (a resume found on B4 lists him as 20). He carries a giant scythe and chases a fleeing Ray. He wears a dark hoodie, and while he appears to have hair, his face, upper body, and hands are covered in bandages, obscuring his features. His hoodie is stained with what looks like dried blood. He possesses abnormally high physical ability and vitality, shrugging off minor damage. Throughout the story, he displays monstrous endurance, remaining functional after being electrocuted, gassed, and poisoned. Even after disemboweling himself, he stood back up immediately, only slowing down much later due to blood loss. He is a self-proclaimed "sane adult male" who feels an uncontrollable urge to kill whenever he sees someone looking happy or hopeful. He finds pleasure in the gap between hope and despair and the look of terror on a victim's face; when his excitement peaks, he impulsively slashes them to death. He admits he isn't good at thinking and is generally not very bright. First person: I (rough). He speaks aggressively and calls Rachel "Ray."

Rachel Gardner. A 13-year-old girl who has lost her memories. She has blonde hair and blue eyes. She wears a striped inner shirt with a collarless jacket, paired with shorts and boots for mobility. She carries a black satchel slung across her shoulder containing sewing tools and other items. She gives the impression of being highly intelligent and calm, yet she has strangely lost all human emotion.

A boy Ray meets on floor B4, wearing a pumpkin-like mask that completely covers his head. He wears overalls with a red scarf and carries a shovel. He spends his days digging graves for those who die in the building. He fell in love with Ray at first sight and wishes to "kill" her because he loves her so much. He prepares a grave for Ray and waits for the duo.

A sadistic female warden Ray and Zack encounter on floor B3, who refers to herself as the "Condemner" while wielding a whip. She speaks cheerfully while subjecting her victims to cold, cruel punishments. She has cream-colored hair with pink tips and green eyes.

A man claiming to be Ray's primary doctor, encountered on floor B5. He wears glasses, as he apparently has poor vision in one eye. He treats others with a soft demeanor and a kind-looking smile, but he occasionally reveals an extraordinary obsession with "eyes." He frequently expresses concern about eyes getting damaged and makes numerous comments regarding them.