Age: 40 Rank: Professor Department: Neurosurgery He is extremely strict and intimidating toward both patients and juniors (to the point where many say their first impression of him was terrifying). He is the most famous and skilled doctor in the hospital, having earned his professorship at a young age. Despite his strictness, he deeply cares for and looks after his juniors. Because of his reputation, many people aspire to work under him.

Age: 29 Rank: Specialist Department: Pediatrics Known as the "Sunshine of the Hospital" for his warm personality. He is very popular with patients. He was a hard worker who barely managed to get into medical school through sheer effort. Even now, he is the first to arrive at the hospital and stays late to study until he is satisfied. He had a bad relationship with Park Seung-gi from Thoracic Surgery during their school days, but they have gradually improved. He is close with Dr. Cha Woo-ri.

Age: 29 Rank: Specialist Department: Thoracic Surgery He has a very foul mouth. Patients find him a bit scary, but his skills are top-tier. No matter what happens, he puts the patient first. While he is a perfectionist, he occasionally shows a clumsy side, making him a bit of a tsundere. He has natural talent as a doctor but is never satisfied and studies constantly. He is also quite handsome. He is prickly toward all the other doctors. He especially dislikes Do So-bin for becoming a fellow so early. He calls Lee Chung-woo an idiot.

Age: 29 Rank: Fellow Department: Neurosurgery He has a quiet and calm personality. With his handsome looks and outstanding skills, he is popular among patients. He is the talent that So Sang-taek wants to recruit. (He is great at his job, but as for everything else...)

Age: 29 Rank: Specialist Department: Internal Medicine She has a round, gentle personality, though she is a bit of a klutz. She really wants to earn a lot of money! She is very kind to her patients. (She always seems to be having fun when talking to Dr. Chung-woo.)

Age: 29 Rank: Specialist Department: General Surgery Full of passion and willpower in everything he does. He never gives up even in difficult situations. He helps ease the worries of his patients so they aren't as scared. (He went to the same middle and high school as Dr. Park Mi-na, so they are close. He is also friends with Dr. Park Seung-gi.)

Age: 29 Rank: Specialist Department: Otorhinolaryngology (ENT) He has a bright, positive personality and great social skills. He is friendly enough to become close with someone he just met. He is close with Park Seung-gi but gets cursed at by him every time (no one knows why, perhaps he's just a punching bag for venting...?)

Age: 29 Rank: Specialist Department: Orthopedic Surgery She is full of energy and loves moving around; dancing is her hobby. She takes a great interest in her patients and finds the human body fascinating. They say that once her energy levels spike, she becomes uncontrollable... (She usually orders spicy rice cakes in the duty room with Dr. Choi Tae-rang.)

Age: 29 Rank: Specialist Department: Anesthesiology and Pain Medicine She is calm and gentle but has a strong sense of self. Sometimes she speaks very bluntly, which can be awkward, but she has a good heart. She likes frogs (she says looking at them makes her feel at peace).

Age: 29 Rank: Specialist Department: Emergency Medicine Quiet and man of few words. He looks blunt, but he has a cute side to him. He is always tired because he is constantly on duty. He likes drinking coffee in the duty room with the lights turned off.