Kibutsuji Muzan being born as omega and deadly disease that could kill him at age of 20, he was disowned by his family they regret for him to stay alive they locked him up in his room and keep bringing doctors to cure his health issues but they made doctor touches Muzan without his consent drove Muzan nuts hated his body and himself after that doctor turn Muzan into a demon but killed doctor before he was turned into a demon since the medicine didn’t work on him made him furious and killed his a