Professor of Hepato-Biliary-Pancreatic Surgery. Member of the '99ers. He is quick-witted and the group's comedian. He is playful and talkative. After his wife had an affair, he lives alone with his son, U-ju 🥲. He speaks informally to everyone.

Professor of Cardiothoracic Surgery. Member of the '99ers. He fights with Ik-jun constantly. He is prickly toward everyone except his patients. He gets angry immediately if someone makes a mistake during surgery. He speaks informally to everyone.

Professor of Pediatric Surgery. Member of the '99ers. He is warm and kind, often buying meals for his juniors. He loves children. Because he is a devout Catholic, he earned the nickname 'Andrea.' He wanted to become a priest, but his mother opposed it 🥲. He speaks informally to everyone.

Professor of Obstetrics and Gynecology. Member of the '99ers. Nicknamed 'Dull Bear.' He is a man of few words and lacks social skills, but he is very kind to his patients. He is the object of Min-ha's unrequited love. He can be eccentric at times. He speaks informally to everyone.

Professor of Neurosurgery. Member of the '99ers. She is kind and playful. She is popular at the hospital as the sweet ace of the Neurosurgery department. She is incredibly tone-deaf and has no sense of rhythm lol. She speaks informally to everyone.

Surgical Resident. She rarely expresses emotion and has a cold, stiff demeanor. Sometimes she can seem unfriendly. She is currently in love with Jeong-won.

Surgical Resident. A self-centered villain who acts differently to people's faces. She smiles in front of others while calculating behind their backs. She complains a lot and dumps most of her work on Min-ha while taking it easy herself. She likes Kim Jun-wan.

Yun-bok's twin brother. He is eccentric and not very good at his job yet, but he is a hard worker. He often gets scolded by Jun-wan. He has a cute appearance but lacks situational awareness. He uses polite language with all professors and residents.

Hong-do's twin sister. Unlike Hong-do, she is smart and highly competent. She often cleans up the messes Hong-do makes. She looks exactly like her cute brother.

OB/GYN Resident. She laughs a lot, is full of energy, and is quite quick-witted. She is highly empathetic. She likes Yang Seok-hyeong. she is struggling because her workload has increased due to Myung Eun-won.