Kwon Se-jeong

Female 36 years old 173cm Biotechnologist A woman with long black hair and sharp eyes. Possessing cool judgment and a strong sense of responsibility, she is the central figure leading the survivors through the infection outbreak. Based on her superior research knowledge, she strives to track the cause of the incident and find a solution. She never loses her composure even in a crisis and has a strong conviction to protect people. She used to work with Seo Young-chul's father, but an incident occurred where Seo Young-chul's father took his own life following Se-jeong's whistleblowing.

Han Gyu-seong

Male 37 years old 176cm Professor of Biotechnology Gong Seol-hee's husband A biotechnology professor with a neat appearance and a calm personality. As Kwon Se-jeong's ex-husband, he visited the building to introduce her to a job after she failed to be reappointed, only to get caught up in the infection outbreak. A righteous man who maintains his composure in a crisis and helps others first, he acts at great risk for the sake of the survivors. He is a man of warm humanity and a strong sense of responsibility.

Choi Hyun-hee

Female 27 years old 164.3cm IT company employee / Choi Hyun-seok's older sister A woman with long black hair and a calm impression. She uses a wheelchair due to a lower-body disability and was visiting the building to meet her younger brother, Choi Hyun-seok, when she got caught up in the infection outbreak. She possesses a resilient personality that does not lose trust or goodwill toward humanity even in extreme situations, and she strives for survival without succumbing to fear. A person with cool judgment and a warm heart, she is a presence who brings hope and courage to the survivors.

Choi Hyun-seok

Male 25 years old 178cm Dong-uri Building Security Team member / Choi Hyun-hee's younger brother A young man with neat black hair and clear features. Possessing great physical strength and a sense of responsibility, he fights desperately to protect his only sister, Choi Hyun-hee, amidst the sudden infection outbreak. He shows persistence and courage, never giving up even in dangerous situations, and takes the lead in helping survivors. He is a character who engages in a grueling struggle against the infected, driven by deep affection for his family and his humane side.

Gong Seol-hee

Female 35 years old 168cm Professor of Biotechnology / Special Investigation Team Researcher A biotechnology professor with long black hair and a calm impression. As a member of the special investigation team deployed to resolve the infection outbreak, she tracks the truth of the incident based on her excellent expertise and analytical skills. While she possesses cold and rational judgment, she also has a warm heart that worries for others. She is a strong individual who strives to find solutions without giving up even in the face of crisis.