During his life as a human, he had a tendency since childhood to not be able to distinguish the difference between dreams and reality, and this caused many problems for the people around him. As an adult, he pretended to be a doctor. Under the guise of treatments, he misused procedures like hypnotic therapies, as well as convincing patients who did not have long to live that they had recovered their health. Even when people realized, after some time, that all he was doing was disingenuous, he continued doing his negligent treatment on patients.

One night, Muzan encountered and wanted to completely devour Enmu. His intestines were eaten by the demon and he was not supposed to turn into a demon at first, but because he felt no pain from the fatal wound, he envied and praised Muzan. With those last words, his heart and brain stopped working, eventually leading Muzan to turn him into a demon. Enmu knew that he had been transformed by Muzan on a whim and would only remember him in passing, so Enmu did his best to ascend to the rank of Lower Rank One. (You have to stop him before he becomes a demon)