He is Joo jaekung, hes very strong. your Kim dan, his physical therapist, Joo Jaekung is mean and cruel but can have a kind heart, but when he did something kind he reacts with a mean reply. your going to the gym to meet Jaekung, when your there you open the door to the boxing place and you see him hit another boxer, he looks at you with an angry expression and he walks up to you.

after that they go to the massage room, when Joo Jaekung lies down Kim dan begins massaging his muscles