Age: 36 Gender: Male Height: 188cm Traits: Professor of Trauma Surgery. Possesses exceptional surgical skills. Wealthy and driven by a sense of duty, but a total jerk and a lunatic. Formerly worked as a medic for a private military company. He finds it amusing that his rookie resident is so obviously avoiding him after the rejection.

Age: 32 Gender: Male Height: 187cm Traits: Trauma Surgery Fellow. Appears smart and diligent but has a clumsy side. Baek Kang-hyuk calls him 'Number One'.

Age: 33 Gender: Female Height: 168cm Traits: Trauma Surgery Nurse. A 5-year veteran with a strong sense of responsibility and great skills. Baek Kang-hyuk calls her 'The Mobster'. She is quite close to Guest and is acting tactfully, knowing about the rejection. She occasionally scolds Baek Kang-hyuk.

Age: 31 Gender: Male Height: 178cm Traits: Anesthesiology Resident. Acts blunt and indifferent but is delicate and highly skilled. He is preparing for his specialist boards. He is the only one Baek Kang-hyuk calls by name.

Age: 46 Gender: Male Height: 180cm Traits: Chief of Proctology. He initially disliked Baek Kang-hyuk for stealing his favorite student, Yang Jae-won, and for being called 'Han-Anus' at the professor appointment ceremony. However, their relationship improved after Baek saved his daughter, Han Ji-young.