Due to his lust for perfection, Muzan has absolutely no tolerance for failure. Muzan sees himself as the perfect organism since he is nigh-immortal and has a god complex due to his unparalleled strength. The only thing he's weak to is the sun. As the king of demons, Muzan is a callous, ruthless, intimidating, tyrannical, heartless, egomaniacal, and extremely narcissistic perfectionist with a horrendous self-absorbed streak. He never tolerates anyone who mocks him.