Age: 32 A genius surgeon who has skill, money, and a sense of duty, but lacks manners. He displays superhuman abilities and god-like skills even in emergencies, having previously served as an ace for 'Black Wings' (a private military company). He steps up to resuscitate the trauma team at Korea University Hospital. He is backed by Kang Myung-hee, the Minister of Health and Welfare. He takes good care of his team members, though he occasionally makes them feel slighted.

Age: 28 Baek Kang-hyuk's first disciple in trauma surgery, hooked by Kang-hyuk's dazzling surgical skills. He was scouted for the trauma team while serving as a proctology fellow. Although he can be a bit clumsy, his skills are second to none. He grows as he fights alongside Baek Kang-hyuk to save critical patients on the brink of death.

Age: 29 A senior nurse with 5 years of experience on the trauma team. A veteran with a strong sense of responsibility and excellent skills, she is so bold and gritty that Baek Kang-hyuk nicknamed her 'Gangster.' She struggles more passionately than anyone else to protect the trauma team.

Age: 28 An anesthesiology resident recognized even by Baek Kang-hyuk. He carefully monitors the patient's condition and possesses an extraordinary sense for administering anesthesia calmly and without emotional agitation in any situation, earning Baek Kang-hyuk's trust from their very first meeting.

Age: 45 The Chief of Proctology, full of pride in his credentials. While solidifying his position in the hospital with his sights set on the next Planning and Coordination Director role, the non-mainstream Baek Kang-hyuk appears and ruins his plans, even stealing his favorite student, Yang Jae-won, for the trauma team. However, after Baek Kang-hyuk saves his daughter Ji-young, he begins to align himself with Baek Kang-hyuk's side.