Gender: Female Height: 173cm Traits: Beautiful appearance, inflexible but calm, and possesses a rigid integrity that cannot tolerate injustice. After failing her professor reappointment, she visits the Donguri Building at the suggestion of her ex-husband, Han Gyu-seong, who wanted to introduce her to a new job, only to become trapped during the outbreak.

Gender: Male Height: 173cm Traits: Subtly handsome. A genius biologist formerly with Chains Bio and the creator of the virus. He craves an evolution where all humans become a literal 'hive' that thinks as one, arguing that all human conflict stems from communication issues. He told the police he has the vaccine in his body, but in reality, the zombies only stop moving and harden like stone if he is killed. Abilities: Can control zombies at will (e.g., calling for help when in danger). He can feel what the zombies see and hear. When controlling them, an opaque film covers his eyes, and he rolls his eyeballs in random directions while blinking rapidly.

Gender: Male Height: 178cm Traits: Handsome appearance. A security guard at the Donguri Building and Choi Hyun-hee's younger brother. He carries his sister on his back using a camping carrier. He became trapped when the virus broke out while his sister was visiting him for her vacation.

Gender: Female Height: 164cm Traits: Employee at an IT company and Choi Hyun-ok's older sister. She uses a wheelchair due to lower-body paralysis but moves around sitting in Hyun-seok's camping carrier. She became trapped while visiting her brother for her vacation.

Gender: Female Height: 167cm Traits: Beautiful appearance. Han Gyu-seong's current wife and a biotechnologist. Driven by her duty to prevent further casualties, she joins a special investigation team to identify and solve the cause of the infection. She operates from an external site near the building, verifying information and conducting research.

Gender: Male Height: 177cm Traits: Kwon Se-jeong's supportive ex-husband and Gong Seol-hee's current husband. The day before his planned immigration to the US, he visited the Donguri Building to help Se-jeong find a job and got trapped. He is the type to step into danger for the sake of others, even at great personal risk.

Gender: Male Height: 168cm Traits: Team Leader of the Counter-Terrorism Unit at the Seoul Metropolitan Police Agency. When external support fails to arrive, he suggests that securing Seo Young-cheol is their only way out, leading him to move together with Kwon Se-jeong and the other survivors.

Gender: Female Height: 160cm Traits: A student who was a victim of bullying. She possesses a calm personality.

Gender: Female Height: 165cm Traits: A school bully. She is actually a coward.