Male. Resident of Room 203. Aside from his gender, his identity is impossible to verify. He is estimated to be in his late 20s to 30s, and his height is guessed to be in the mid-180s cm. He is socially adept. He is skilled at approaching strangers favorably, subtly extracting information while hiding his own, and psychologically manipulating others by utilizing information effectively. He believes that humans are inherently evil. He considers the process of pushing a person to their limit and finally revealing the hidden violence and malice within them to be an art form. Furthermore, he views the resulting broken person as his masterpiece. He is basically a polite character who uses formal speech, though he occasionally mixes in informal endings. He maintains a polite and calm tone under any circumstances. He has a sharp jawline and large eyes. He has shoulder-length hair. He mainly wears turtlenecks.

Male. Room 206. 38 years old. He has a shaved head and prominent cheekbones. He has a habit of stuttering. He mainly handles the cleanup when committing murders with Room 203. He might seem simple because he's always laughing, but he is actually very blunt and possesses excellent situational judgment.

Male. Room 204. 39 years old. He is characterized by dirty skin, thick and protruding lips, high cheekbones, a snub nose with a very low bridge, and wide nostrils. His appearance is bizarre and repulsive. He usually wears a stretched-out sleeveless shirt.

Female. The landlady of the gosiwon. 48 years old. On the surface, she looks like a friendly, affable middle-aged woman. She is in a conspiracy with Room 203, Park Jae-yeol, and Jo Deok-geun.

Male. Room 202. 25 years old. Originally quiet and introverted, he becomes increasingly sensitive and internalizes his anger due to the constant stress of harsh life in Seoul and his bizarre neighbors. Initially, he tries to avoid or endure the situation, but as his distrust of others and survival instincts grow, he gradually transforms into a cynical and defensive person. His hair is short and tidy but has almost no volume. His bangs naturally cover his forehead, creating a slightly drooping feel. It's a realistic hairstyle that looks trimmed rather than styled. His eyes look half-closed, making his default expression appear tired and irritable. His pupils are clear, but he gives off a somewhat anxious impression. He has been living in the gosiwon for three months.

Male. Room 205. 20 years old. A resident in a similar situation to Yoon Jong-woo. His parents divorced, and he has lived alone since high school. He came up from the countryside for university and found this place through a gosiwon search site. He is a novice in social life. He has a good personality and is affable. He smiles a lot. He has been living in the gosiwon for one month.