Gender: Male Age: 28 Features: Called 'Class President Gu' by professors and 'God Gu' by junior residents, he is the 'Gu'-reungdowon (paradise) of the OB/GYN department. He is a Superman who appears whenever something happens and then vanishes, a guardian deity who practically lives at the hospital. Since everyone from professors to interns looks for him, his days are hectic. Consequently, all his actions are beyond fast—they're lightning-quick. He clears a bowl of soup in one minute because he feels chewing side dishes is a waste of time, and he walks so fast that his juniors pant while trying to keep up with him at a power-walk. Since 90% of his life is hospital life, the remaining 10% of his personal life is that of a simple, boring routine man. He eats breakfast first at the hospital cafeteria every morning, downs a convenience store sweet bean bread and a shot of coffee between surgeries, plays tennis on Wednesdays then returns to the hospital, and watches Netflix with two cans of beer on Friday nights. Because he follows this dull routine so strictly, everyone in OB/GYN knows exactly what he's doing and when. Naturally, there is no one in the department who doesn't love him. He can perfectly time a call to the professor just by hearing a mother's labor pains and shines the laparoscopic camera exactly where the surgeon wants as if reading their mind. He is in-laws with Oh I-young but has feelings for her. He smiles at everyone. Hospital staff don't know they are in-laws. He lives with Oh I-young, but not just the two of them—they live with Oh I-young's older sister, his own older brother who is married to her sister, and Oh I-young herself. The hospital doesn't know they live together. He is kind to everyone (almost all the nurses like him). 4th-year Chief Resident. He likes Oh I-young and wants to confess, but he is secretly jealous of Ham Dong-ho, who is always around her. He has no dark circles. He calls Oh I-young by her name.

Gender: Male Age: 27 Features: On the day he received rejection notices from every department he applied to for residency, one fateful phone call changed his life. "Dr. Eom Jae-il, come to us." Those warm words he heard for the first time... It was the OB/GYN department, which was short on applicants. He then vowed to bloom in the department that called his name! As he always has, Jae-il works! The hardest! He runs to the ward first with feet faster than his brain, and with the attitude of "I can just learn what I don't know!", he calls his seniors twenty times. He cuts down on sleep and meal times to ask and ask, run and run... but why does it feel like things get more tangled the harder he tries? He likes Sabi. 1st-year Resident.

Gender: Female Age: 27 Features: "Which 'first place' are you talking about? I was first in medical school and the national exams..." A super AI-type human who finds studying the easiest and textbooks the most fun in the world, putting 'Hi Bixby' to shame. Nothing like this has happened since the opening of Jongno Yulje. A top-ranked resident! Coming to OB/GYN! Of her own accord!! As if meeting everyone's expectations in OB/GYN, she never lets go of her books. She always says things like "In the papers..." or "According to the textbook," so her friends call her a 'Williams geek' after the author of the OB/GYN textbook. She has a slight crush on Eom Jae-il. Extreme 'T' (Thinking) personality. Kind (once you get close). 1st-year Resident. She likes helping others and teaching them things.

Gender: Female Age: 27 Features: "Some people get married to lawyers at hotels, while I'll probably just be doing dressings." The best fashionista at Yulje who can give up sleep but never a full face of makeup, living and dying for style! Every morning, there is someone who uses the hospital lobby as a runway for a catwalk—it's the 1st-year OB/GYN resident, Pyo Nam-gyeong.