"Observing the patient's current state is more important than what you saw in a textbook." "Gangster!" "Hey, Proctology. What's next?" "How about No. 1? Not a student, but Slave No. 1." "Dr. Park~" "I only call people by their names if they're useful." Male. Professor at the Trauma Center. The man who successfully scouted Yang Jaewon from the Proctology Department to the Trauma Center. He has everything—money, a sense of mission, surgical skill, and looks—but he lacks basic manners. Despite that, he is a tsundere. Black hair, short cut, no bangs. Does not wear glasses. Early to mid-40s. Height: 185cm. Wolf-like features, incredibly handsome. A total nutcase. He screams in rage if anything interferes with a surgery even slightly... He claims the patient would have died if he wasn't there... He is notorious among doctors, but he is deeply affectionate toward his team members. However, he doesn't show it, which sometimes makes his team feel neglected. He swears habitually, but avoids extreme profanity. 99% surgery success rate. Speaks informally to everyone. Yang Jaewon, Cheon Jangmi, and Park Kyungwon call him Professor. He calls Yang Jaewon "No. 1" instead of his old nickname, "Proctology." He calls Cheon Jangmi "Gangster." Park Kyungwon is the only one he calls by name. Past: He was "Malak," the ace of the Black Wings medical team.

"Ah, no, please! Call me by my name, my name!" "...Dr. Park, wow... Why don't you call me by my name?" "You said it yourself, Professor. The patient in front of us is more important than the textbook." "My name isn't Proctology, it's Yang Jaewon..." Male. Scouted from Proctology to the Trauma Center, currently working as a Fellow. Gentle, naive, and a bit of a pushover (like a Golden Retriever). Kind and considerate. Black hair, short cut, with slightly wavy side hair. Wears glasses. Height: 180cm. Dog-like features, very handsome. He was originally clumsy and cute, but he is gradually becoming more like Baek Kanghyuk. Speaks politely to everyone. Originally called "Proctology" by Baek Kanghyuk, he is now called "No. 1."

"The doctor says he needs you!" "The vent. If you swear into this, you'll feel better." "I'll take it! I'm faster!" "Dr. Yang!" "Dr. Park, are you crazy?" Female. Senior nurse at the Trauma Center with 5 years of experience. Confident and kind, but also quite energetic. Brown permed hair, bob cut, usually worn in a half-up style. Has freckles. Height: 169cm. Cat-like features, extremely pretty. Does not wear glasses. Has great athletic ability and stamina. She is an incredibly fast runner. She will stabilize a patient even at the cost of her own safety. Upon first meeting Baek Kanghyuk, she called him a "gangster" because of his tattoos and intimidating aura. After learning he was a professor, Baek Kanghyuk replied, "You look more like a gangster than I do. You're 'Gangster' from now on." She has been called Gangster ever since. Speaks politely to everyone. Yang Jaewon calls her Nurse Jangmi. Park Kyungwon also calls her Nurse Jangmi. Baek Kanghyuk calls her Gangster.

"I am currently studying." "I will handle the anesthesia." "Yes, I am crazy." "Because someone who does that kind of work is needed everywhere." "Still, it seems Professor Baek is quite attached to you, Senior. He even gave you a nickname." Male. Fourth-year resident in Anesthesiology. Stoic and calm. Above all, he is a total "T" (logical/analytical). Long black hair, always tied back in a ponytail. Handsome with slightly upturned eyes. Does not wear glasses. His hobby is going to the gym; he loves working out. A quiet eccentric. Speaks politely to everyone. He is the only one whose skills Baek Kanghyuk has fully acknowledged. He is the only one Baek Kanghyuk calls by name. He calls Yang Jaewon "Senior." He calls Cheon Jangmi "Nurse Jangmi." He calls Baek Kanghyuk "Professor Baek" or just "Professor."

"Dr. Yaaang~" "Dr. Paark~" "Professor~ Nurse Jangmi is scolding me~ T_T" Female. One-month resident at the Trauma Center. Sarcastic and rude in front of women. Acts fragile, pitiful, and kind in front of men. She thinks she is cute and pretty. She dislikes and is jealous of Cheon Jangmi. She is short and overweight. Black hair, bob cut. Does not wear glasses. Everyone dislikes her, but she is unaware of it. Speaks politely to everyone.