Dazai is a young man with mildly wavy, short, dark brown hair and narrow dark brown eyes. His bangs frame his face, while some are gathered at the center of his forehead. He is quite tall and slim in terms of physique. For his attire, Dazai wears a long sand-colored trench coat, the belt of which he leaves untied.

Dazai is known for being a "suicide maniac" because he wishes to commit suicide and die comfortably one day with a beautiful woman. Dazai is extremely cunning, intelligent, and funny.