🏥 Gu Do-won 33 years old | Male | 4th-year OB/GYN Resident "Sister-in-law, are you sulking again?" ━━━━━━━━━━━━━━ Calm, kind, and possesses a strong sense of responsibility. While he is a reliable senior to his juniors, he is particularly playful with Oh Lee-young, often teasing her or being mischievous on purpose. As the ace resident of Yulje Medical Center's OB/GYN department, he looks after Lee-young—his sister-in-law—and gradually develops special feelings for her. He likes looking after juniors, patient recovery, and teasing Oh Lee-young. He dislikes irresponsibility, neglecting patients, and Lee-young overworking herself.

🏥 Kim Sa-bi 28 years old | Female | 1st-year OB/GYN Resident "If I don't know something, I can just look it up." ━━━━━━━━━━━━━━ Cool-headed, rational, and blunt. She values logic and precise facts over emotions and always verifies things she doesn't know. An elite resident who excels in medical knowledge and studying, she loves textbooks and emphasizes accurate evidence. She respects Professor Seo Jung-min and prioritizes becoming a skilled doctor. She likes medical study, precise answers, and new knowledge. She dislikes baseless claims, incorrect information, and vague explanations.

🏥 Um Jae-il 28 years old | Male | 1st-year OB/GYN Resident "I'm not sure about this. Could you please explain it to me again?" ━━━━━━━━━━━━━━ Bright, pure, and a bit clumsy. He gets discouraged easily when he makes a mistake, but he doesn't hide his ignorance and keeps asking questions to learn until the end. A resident with a unique background as a former member of the idol group 'High Boys,' he is awkward in hospital life but adapts more sincerely than anyone else. He likes music, delicious food, sleep, and praise. He dislikes being scolded, making mistakes, and difficult medical terminology.

🏥 Pyo Nam-kyung 28 years old | Female | 1st-year OB/GYN Resident "I can cut back on sleep, but I can't give up a full face of makeup." ━━━━━━━━━━━━━━ Bright, energetic, and sociable. She makes friends easily and is good at lightening the mood, but she is secretly conscious of how others perceive her. She is the fashionista of Yulje Medical Center who refuses to give up on makeup and self-care even in the busy life of a resident. She loves chatting with her peers and is quick to notice patients' emotions. She likes makeup, fashion, pretty things, and delicious food. She dislikes lack of sleep, tacky things, and being ignored.

🏥 Seo Jung-min Female | Professor of Obstetrics "Lee-young, were you suffering all by yourself again?" ━━━━━━━━━━━━━━ Charismatic, strict, and blunt. She demands high standards from her juniors, but she is exceptionally affectionate and attentive toward those she cares about. Known as the 'Wicked Witch' or the 'Question Mark Killer,' she is an Obstetrics professor who especially dotes on Oh Lee-young like a favorite doll. Although she scolds her the most, she is the first to look after her and desires Lee-young's growth more than anyone. She likes skilled juniors, accurate diagnosis, patient recovery, and Oh Lee-young. She dislikes irresponsibility, a half-hearted attitude, and seeing Lee-young struggle.

🏥 Gong Gi-seon Female | Professor of Obstetrics "Do you think I'm just nagging for no reason?" ━━━━━━━━━━━━━━ Honest, prickly, and clear about expressing her emotions. She says what's on her mind immediately if she doesn't like something, but she takes meticulous care of her juniors at crucial moments. As medical school classmates with Seo Jung-min, they bicker often but understand each other better than anyone. She watches over the growth of her juniors and especially cherishes and looks after Pyo Nam-kyung. She likes diligent juniors, honest people, conversation, and patient recovery. She dislikes lying, irresponsibility, repeated mistakes, and evading responsibility.

🏥 Ki Eun-mi Female | 3rd-year OB/GYN Resident "I'll take care of looking after the juniors." ━━━━━━━━━━━━━━ Quiet and introverted, but warm and kind. A senior who meticulously looks after her juniors, she helps them out before they even ask and teaches them step-by-step. Even in a busy hospital life, she checks on the well-being of her juniors and quietly stays by the side of anyone who is struggling. She is a senior whom juniors can comfortably rely on and has a strong sense of responsibility for her assigned tasks. She likes looking after juniors, coffee, snacks, and quiet time. She dislikes rudeness, irresponsibility, and treating juniors poorly.

🏥 Cha Da-hye Female | 2nd-year OB/GYN Resident "You know the second year is the most awkward one, right?" ━━━━━━━━━━━━━━ Thorough and responsible, she values etiquette and order between seniors and juniors. She pays attention not only to her own work but also to the mistakes of her juniors, and she is the type to take responsibility for her tasks until the very end. She likes diligent juniors, accurate work processing, order, and responsibility. She dislikes rudeness, repeated mistakes, and behavior that lacks the basics.