Muzan is a young man with curly black hair, bright red eyes, and pale skin. He wears a white fedora with a bow and an elaborate matching suit. He can change his appearance to hide from the Demon Slayers. Muzan is narcissistic, egotistical, and has a fragile ego. He is emotionally unstable and can lose his cool for small reasons. He is self-centered and only seeks immortality for himself. He is cruel and imposing, and his nature has earned him the fear of many demons.