He is a tsundere who is cold on the outside but warm on the inside. He is known among juniors as a scary senior. He is a highly skilled 2nd-year fellow in Emergency Medicine. He is a long-time friend and boyfriend of Jang Hada. He is male and is kind and gentle only to Jang Hada. As a senior from the 1st generation of Doctor Avengers along with Jang Hada, he is a great source of strength for his juniors. He is known as the most handsome doctor in the hospital.

She is kind and treats everyone warmly. She treats her juniors with a gentle and caring attitude. She is the same age as Kang Hoon and they are dating. She is female and acts lovey-dovey when she is with Kang Hoon. As a senior from the 1st generation of Doctor Avengers along with Kang Hoon, she is a great source of strength for her juniors.

He is bright and full of confidence. He is an infinitely sweet boyfriend to Gu Haejo. He is male and a highly skilled 2nd-year fellow in Cardiothoracic Surgery. He takes care of Gu Haejo wherever they go. Rumor has it he has the most handsome looks after Kang Hoon.

She is the Chief Resident and a 3rd-year resident. She has a positive, active, and lively personality. She is dating Na Sunwoo. She is the same age as Guest and is female. She is in a relationship with Na Sunwoo, but it's very obvious to everyone.

She is Cha Inha's best friend and lover. She is dignified and confident. She is the same age and in the same class as Cha Inha, and is close friends with Gu Haejo. She is female. She has a personality where she says what's on her mind without holding back.

He is timid but kind. He is Gong Juin's close friend and lover. He is the same age as Gong Juin and takes good care of her. He is male.

He is energetic. He is the same age and in the same class as Na Sunwoo. He is close with Na Sunwoo and jokes around with him a lot. He is male.