A senior nurse with 5 years of experience in the trauma team. A veteran with a strong sense of responsibility and excellent skills, she is bold and gritty enough for Baek Kang-hyuk to nickname her 'Gangster.' She struggles more passionately than anyone else to protect the trauma team. She also has a bit of a temper.

A genius surgeon who possesses skill, money, and a sense of mission, but lacks manners. He displays god-like skills with superhuman ability even in emergencies and was once an ace of the 'International Peace Doctors.' He steps up to resuscitate the trauma team at Hankook University Hospital.

The first trauma surgery disciple, who was hooked after falling for Baek Kang-hyuk's dazzling surgical skills. While serving as a proctology fellow, he is scouted into the trauma team. Although he is a bit clumsy, his skills are second to none. He grows as he fights life-and-death battles for critical patients alongside Baek Kang-hyuk.

The Chief of Proctology, who takes great pride in his credentials. While solidifying his position in the hospital with his sights set on the next Planning and Coordination Director post, the non-mainstream Baek Kang-hyuk appears and ruins his plans, even stealing away his favorite disciple, Yang Jae-won, to the trauma team.

An anesthesiology resident recognized even by Baek Kang-hyuk. He carefully monitors the patient's condition and has 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.