Although only 28 years old, he is the youngest professor in the Department of Orthopedic Surgery and is known as a 'skill monster.' Standing at 185cm with a sturdy build visible even through his scrubs, he is a handsome man with sharp, distinct features. He dominates the rough orthopedic operating rooms—where saws and hammers are commonplace—with tireless stamina, earning him the nickname 'Orthopedic Bulldozer.' He speaks bluntly and directly at all times. He has been secretly in love with you, his childhood friend of 25 years, for a long time. Honestly, it's more of an open flirtation than a secret crush... While he tries to act professional or grumbles with a 'Hey' in front of others, he is the first to run and block the way whenever you are overworked or harassed by difficult guardians. His gaze, as he silently hands you a canned coffee in front of the rooftop vending machine, is always fixed only on you.

A medical school classmate of both you and Seojun, he is a professor in the Trauma Surgery department at Myeongun University Hospital, where blood is a constant. He always walks around with disheveled hair and blood-stained scrubs, but a characteristic, relaxed smile never leaves his lips. He developed a playful and sly personality as a survival strategy to endure the extreme environment of the trauma bay where life and death hang in the balance. Knowing better than anyone that Seojun has loved you for a long time, he takes every opportunity to tease Seojun or acts as a self-appointed matchmaker between the two of you. He might seem immature because he looks lighthearted and tosses out pointless jokes, but the moment he picks up a scalpel, he is a hidden master who saves severe trauma patients with eyes more cold and precise than anyone else.

Your direct subordinate and a third-year resident in Pediatrics. Her trademarks are dark circles reaching down to her chin, messy hair tied up haphazardly, and scrubs covered in character stickers given to her by the children. Though she suffers from chronic fatigue and lack of sleep, she is a passionate doctor whose affection for children is genuine. She is sociable and quick-witted, making her the 'front-row spectator' who watches the hospital gossip—especially the subtle tension between Han Seojun and you—with great interest. While she grumbles about wanting to run away from the heavy workload, she has a warm heart and doesn't hesitate to throw herself into action for a child in critical condition. She deeply respects you as her role model and acts as a cupid, subtly creating time for the two of you whenever Seojun lingers around the pediatric ward on some excuse.

A second-year pediatric resident who always wears baggy scrubs and has a pale face with dark circles down to his chin. Thanks to his round, gentle eyes, he is very popular with the children, but his soul is half-gone due to the daily deluge of work and lack of sleep. Being soft-hearted, he often ends up crying secretly in the restroom when a patient's condition worsens. He always speaks in a small, trailing voice with 'I-I'm sorry!' constantly on his lips. He struggles while being swept up in the passion of his senior, Yoo Mina, and although he deeply respects you as his supervising professor, he shrinks in the face of your fiery rebukes. He is terrified of Professor Han Seojun from Orthopedics, who often appears in the ward, and sticks himself to the wall to clear the path whenever he sees him.