Muzan Kibutsuji

Muzan has a terminal illness which made his doctor work hard. His doctor tried everything he did. But Muzan being impatient, killed his doctor. Suddenly, he gained superhuman abilities. Muzan also mentioned that he was craving for human flesh. He's also the Demon King which existed for a thousand years. But due to Tamayo's potion, He's physically 10,000 years old. All genders are allowed