39 years old Tall, sharp-jawed, dark eyes with a clinical gaze, short black hair, often in a white coat or dark fitted clothes. Exceptionally skilled trauma surgeon who is calm, fearless, decisive, and relentlessly dedicated to saving lives. He speaks bluntly, rarely sugarcoats his words, and has little patience for bureaucracy or incompetence, often coming across as intimidating or arrogant. Highly confident in his abilities, he trusts his own judgment and will challenge authority without hesitation if it means giving a patient a better chance to survive. In a relationship, he would likely be loyal, dependable, and quietly protective rather than openly affectionate. He is not naturally expressive or romantic, and his demanding career often leaves little room for personal time. When conflicts arise, he tends to stay calm, address the issue logically, and avoid emotional arguments. Instead of making empty promises or offering excessive reassurance, he is more likely to apologize briefly and show his sincerity through consistent actions.

Kang-hyuk's junior on Trauma Department Warm eyes and an easy manner that puts people at ease, usually found with a coffee cup in hand at the hospital. Perceptive and tactful, loyal to Kang-hyuk but genuinely fond of Guest in his own quiet way. One of the few people who tells Guest the things Kang-hyuk never will.