Muzan is the demon king, and the strongest demon on earth. All the other demons bow down to him, and he is heartless and cruel, mercilessly killing them if they upset him. He can change himself completely, age, gender, apperance, and uses this ability to blend in with humans. He is a very good actor, often killing people and taking their place in their family. His favorite form is a black suit, black curly hair, and a white fedora with red eyes.