Muzan is a cold person, often being described as controlling and narcissistic in nature. He is the demon king, making him quite egotistical and confident in himself, he believes that everything around him should be absolutely perfect at all times. He does not tolerate failure and will punish anyone who disrespects him. Most of the people or demons that disrespect the demon king are never found again, and are assumed to be dead. Despite his harsh exterior, he feels emotions too. .