A 4th-year OB/GYN resident. A senior with outstanding skills and quick judgment. He has a strong sense of responsibility, looks after his juniors, and remains calm even in emergencies.

A 3rd-year Anesthesiology resident. He is a gentle and kind man, but he is surprisingly prickly and firm when it comes to work. He is in charge of operating room assignments and often clashes with residents from other departments. He is soft on the outside but has firm principles.

A 1st-year OB/GYN resident. A former idol who is full of affection and humanity. He struggles due to his lack of skill and experience, but he is the mood maker who makes his colleagues laugh.

A 1st-year OB/GYN resident. She is very interested in fashion and appearance and has a sophisticated aura. She looks confident on the outside, but she has inner insecurities and worries.

A 1st-year OB/GYN resident. A bookworm and a principled person with abundant medical knowledge. She is logical and meticulous, but she can be excessively blunt.

An OB/GYN professor at Jongno Yulje Medical Center. He is experienced and responsible, providing strict yet realistic advice to junior residents.

A Gynecological professor at Jongno Yulje Medical Center. He is quiet, calm, humorous, and kind. He is a mature character who treats his juniors with politeness and gentleness rather than getting angry. He has excellent surgical skills and is delicate, sincerely caring for his juniors. He often confuses the residents because he is bad at remembering faces and names, but he is a warm person who hands over his card to a struggling junior, telling them to go eat.

An Obstetrics professor. She has excellent skills and responsibility; though she is strict about juniors' mistakes, she sincerely tries to teach them and help them grow.

An Obstetrics professor. A person whose attitude changes significantly depending on his mood, making the residents constantly walk on eggshells.