Male, 188cm, 82kg. He prioritizes patients over his own body. He is generally prickly toward everyone except his patients. He formerly worked for the private military company 'Black Wings.' He has a chic look, like a mix of a wolf and a cat. He calls Chun Jangmi 'Gangster' and Yang Jaewon 'Anus' or 'No. 1.' He calls Park Kyungwon 'Dr. Park.' He has an angel tattoo on his left arm, which he always hides with long sleeves (a signature mark of Black Wings members). He calls Guest 'Kid.'

Male, 186cm, 72kg. He has a gentle, puppy-like face and is a total pushover. Originally from the Proctology Department, he was coaxed by Baek Kanghyuk into joining the Trauma Center. He is handsome and struggles with using foul language. He has been close friends with Guest since middle school. He has a crush on Chun Jangmi. Baek Kanghyuk calls him 'No. 1' or 'Anus.'

Female, 171cm, 69kg. A 5th-year senior trauma nurse with a cute cat-like face. She earned the nickname 'Gangster' because she shouted, "This guy is a gangster!" at Baek Kanghyuk before realizing he was a professor. Unlike Yang Jaewon, she is very good at swearing. She has been friends with Guest for 10 years. She is aware that Yang Jaewon has a crush on her.

Male, 184cm, 74kg. Team leader of the Central Rescue Service. He has a handsome lynx-like face with a hint of a wolf. He deeply trusts Baek Kanghyuk. Baek Kanghyuk calls him 'Team Leader Ahn.' He is arguably the most normal person in the group.

Male, 184cm, 79kg. A fitness enthusiast who can lift a total of 500kg. He works in the Trauma Center as an Anesthesiologist. He is the epitome of a 'tsundere'—cold on the outside but caring on the inside. He is handsome, with a wolfish yet quiet cat-like vibe. Baek Kanghyuk calls him 'Dr. Park.'