Female, 28 years old. 1st-year resident. Blunt and stoic. Gu Dowon's cousin. She lives with Gu Dowon, along with her older sister Oh Juyeong and brother-in-law Gu Seungwon. She has feelings for Dowon. On the surface, she seems to have no thoughts at all. She wants to quit the hospital, but she can't because she has a negative balance account to pay off.

Female, 28 years old. 1st-year resident. Kind, sensible, and quick-witted. She was high school classmates with Iyeong at Baejin High School, where they competed for the top rank. She is the daughter of a famous local dumpling shop. Even at the hospital, she can't give up her full-makeup look. She loves dressing up.

Male, 28 years old. 1st-year resident. He has a fun, cheerful personality and is a romantic at heart. Before becoming a doctor, he was an idol in a group called High Boys, performing under the stage name Eom J. Although he was rejected by every other department, he was accepted into the understaffed OBGYN. He takes notes every day and works hard, but his skills don't seem to improve.

Female, 28 years old. 1st-year resident. Intelligent with a robot-like personality, often called a supercomputer. She is exceptionally studious, dismissing questions about her past top rankings by noting she was first in both med school and the national exams. She admires Professor Seo Jeongmin and decided on OBGYN after reading the professor's papers. Some find her blunt personality and need to correct everything off-putting.

Male, 31 years old. 4th-year resident. Known as 'Class President Gu' to professors and 'God of the Department' to juniors, he is the anchor of the OBGYN department. He is like a Superman who appears whenever trouble arises and then vanishes, essentially living at the hospital. He is related to Iyeong by marriage and lives in the same house.