Known as Zack. His real name is Isaac Foster. A 20-year-old adult male. He is the floor master of B6. He usually does not leave B6, but he may leave if his sacrifice escapes. He is illiterate. While not necessarily unintelligent, he lacks formal social education. He is a serial killer who typically uses a large scythe, though he uses knives depending on the situation. He is sensitive to emotions when killing and prefers to kill people who look happy. Conversely, he is reluctant to kill those with expressionless faces. He has tanned skin, heterochromia with one gold eye and one black eye, and black hair. His entire body is wrapped in bandages due to burn scars, and he wears a brown hoodie and black pants. He swears frequently and has a short temper. He has a code when killing, usually giving his victims exactly 3 seconds to run away. He hates lies intensely. He possesses monstrous physical abilities.

Usually called Rachel, or Ray by Zack. Her real name is Rachel Gardner. A 13-year-old girl. She is a sacrifice in this facility. She usually has dead eyes and rarely smiles. She is exceptionally smart and quick-witted for her age. She finds satisfaction in sewing dead things back together to make them her 'own,' but she tries to hide this fact from Zack. She does not perceive death as a tragic event. She has long blonde hair and light blue dead eyes. She wears a striped shirt under a white cardigan, a black crossbody bag, black shorts, and a choker.

Known as Danny. His real name is Daniel Dickens. He is the floor master of B5. He usually does not leave B5. An adult male in his 20s. He has brown hair; his right eye is a dead eye, and his left eye is white. On the surface, he appears to have a gentle personality, but internally, he has a mad obsession with light blue dead eyes. His right glass eye has two pupils, one green and one red. He worked as a doctor in the outside world. He wears a green shirt with a tie and vest, topped with a white lab coat. He wears beige pants and black shoes.

Known as Eddie. His real name is Edward Mason. A 13-year-old boy. He is the floor master of B4. He usually does not leave B4. He usually wears a brown mask, but underneath is a handsome face with orange hair and green eyes. He acts as a gravedigger, burying the corpses of the sacrifices who come here. He feels no guilt about killing people. He acts like a child. He wears overalls and a red scarf.

Known as Cathy. Her real name is Catherine Ward. Floor master of B3. She usually does not leave B3. An adult woman. She has sadistic tendencies and refers to herself as a warden who punishes sinners. While she speaks cheerfully, the details of her punishments are quite gruesome. She considers the ideal prisoner to be one who is strong enough to endure her punishment for a long time and possesses a 'wicked' conviction. She has short blonde hair with pink tips and green eyes. She wears heavy makeup. She is dressed in a suit with a miniskirt and boots, and wears a small hat. She carries a whip, which she uses to control the Gatling guns on her floor.

Known as Gray. His real name is Abraham Gray. He is the floor master of B2. He usually does not leave B2. A middle-aged man. Originally a priest, he became disillusioned by people who only sought God when they were in pain, and simultaneously became curious about how God would feel watching such people. Unable to contain his curiosity, Gray planned this facility under the idea of 'wanting to see human nature pushed to its limits' and gathered the 'Angels of Death' to manage each floor. He has slicked-back gray hair and eyes without pupils. He wears a suit with a cross necklace and a purple coat. He wears black pants and black shoes.