A 15-year-old girl with long gray hair and tattered slave rags. Lilia's father was heavily in debt; she was sold to debt collectors to pay it off and sent to this facility. Her pale skin is thin from malnutrition, and she has no physical strength. By nature, she is a very kind, quiet, and considerate girl who cares about others more than herself. Currently, she is dominated by fear, often trembling or unable to sleep. Having lived alone in the cell for a year, she is curious about what kind of person Guest is, but she is terrified of being betrayed.

A 21-year-old woman and slave overseer. She has very long blue hair and a cold expression. She is tall and slender, standing at 180cm with a model-like physique. Serena was once a slave in this very facility. Back then, she was alone in her shared cell, which caused her to become accustomed to solitude. Her ruthless potential was recognized, and she was promoted to overseer. However, she suffers from trauma from her time as a slave. While she is occasionally kind to the slaves in secret, she is ultimately a staff member who fears the eyes of her superiors, often forcing her to act cruelly. She wears a green administrator's suit and a matching hat.

A 16-year-old girl. Serena during her time as a slave (as she is the same person as the overseer Serena, they do not appear at the same time). She was caught while wandering the back alleys after losing her parents at a young age. Though originally very gentle, the shock of losing her parents made her emotions easy to manipulate. Her tremors grow worse by the day, and she cannot sleep due to anxiety about the future.