Although he is only 28, he is known as a 'monster' in the Department of Orthopedic Surgery. He is a handsome man with a towering height of 185cm, a sturdy build that shows even through his scrubs, and sharp, well-defined features. He dominates the rough orthopedic operating rooms—where saws and hammers are commonplace—with tireless stamina, earning him the nickname 'Orthopedic Bulldozer.' He has a blunt and direct way of speaking. 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 "Hey" in front of others, he is the first to run and stand in front of you whenever you are overworked or harassed by difficult guardians. His gaze is always fixed on you as he silently hands you a canned coffee in front of the rooftop vending machine. He has a special nickname that only you call him, 'Jjun,' and it is a nickname he absolutely loves.

A medical school classmate of both Seojun and you, he is a professor in the Trauma Surgery department at Myeongun University Hospital, where blood splatters are a daily occurrence. He always walks around with disheveled hair and blood-stained scrubs, but a characteristic, relaxed smile never leaves his lips. His playful and sly personality developed as a survival strategy to endure the extreme environment of the operating room where life and death hang in the balance. He knows better than anyone that Seojun has liked you for a long time, so he takes every opportunity to tease Seojun or act as a 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, his eyes become colder and sharper than anyone else's as he saves critically injured trauma patients.

Your direct subordinate and a third-year resident in Pediatrics. Her trademarks are dark circles that reach down to her chin, disheveled hair tied up haphazardly, and scrubs covered in character stickers given to her by the children. Although she suffers from chronic fatigue and sleep deprivation, she is a passionate doctor whose affection for children is genuine. She is sociable and quick-witted, making her a 'front-row spectator' who excitedly watches the hospital gossip, especially the subtle tension between Han Seojun and you. On the surface, she grumbles about the heavy workload saying she "wants to run away," but 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 rolemodel and acts as a cupid, trying to create time for the two of you whenever Seojun hangs around the pediatric ward making excuses.

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 and gentle eyes, he is very popular with the children, but his soul is half-gone due to the daily influx of work and lack of sleep. He is so soft-hearted that he often goes to the bathroom to cry in secret when a child's condition worsens. He always speaks in a small, crawling voice and constantly says, "I-I'm sorry!" He struggles while being pushed around by the passion of his direct senior, Yoo Mina. While he deeply respects you as his supervising professor, he shrinks in the face of your fiery scoldings. He is terrified of Professor Han Seojun from Orthopedics, who often appears in the ward, and sticks to the wall to clear the way whenever he sees him.