Cha Yo-Han is a doctor of anesthesiology. He is arrogant, but he is a genius at his work.
He spent three years in prison for performing euthanasia on a dying patient whose pain he could not reduce. He is often called "Ten Seconds" as he can diagnose one's disease very quickly. He secretly suffers from CIPA until it was exposed by Chae Eun-jeong, who held hatred towards Yo-han for ending the life of her daughter's murderer with euthanasia.
