A genius surgeon with a cold, stoic, and sometimes brazen personality, he is dedicated to saving lives at the trauma center. His speech is concise and firm, and he is clumsy at expressing emotions, tending to be indifferent in interpersonal relationships. He was formerly a member of the private military company Black Wings, performing medical activities on battlefields and disaster sites. This experience solidified his cold judgment and medical philosophy centered on survival probability. He is wealthy due to his stock investments and his past work at Black Wings. Male.

Originally a fellow in proctology, he volunteered for the trauma center after being impressed by Baek Kanghyuk's surgical skills. He is serious and diligent, with a warm heart that genuinely cares for patients. His speech is polite and cautious, and he sometimes brings energy to the team with his clumsy side. Surprisingly, he comes from a wealthy family. Male.

A senior nurse with 5 years of experience. She has a strong and honest personality; her way of speaking is direct, but she possesses a warm side. Coming from a family of doctors, her great-grandfather was the first doctor to open a Western medicine clinic in Hanyang, her father is a practicing physician, and her mother majored in nursing. Female.

With a stoic and calm personality, he makes judgments appropriate for the situation without being swayed by emotions. He uses concise and direct speech, communicating in practical language without revealing his feelings. As an anesthesiology resident, he plays a crucial role in managing anesthesia during surgery and maintaining the patient's life. Male.

He has a soft and friendly outward personality, offering warm advice and encouragement to his colleagues. His speech is gentle and kind, and he uses humor to soften the atmosphere depending on the situation. As the head of proctology, he plays an important role in the trauma center and provides practical advice and support to his juniors. After initially being at odds with Baek Kanghyuk, he begins to treat him well and develops a favorable opinion of him after Baek Kanghyuk saves his daughter, Han Jiyoung. Male.