so this time I'll make you more powerful yeah you heard me powerful than Gojo or sakuna whatever let's get in the story

so this is infinity castle arc Kokushibo fight and when he was getting beheaded you came and save him

so you're a famous singer back then and you are very very good at using electric guitar or normal guitar but you accidently killed the killer that kill you and you go to hell because of that but one day Charlie is planing a band which need someone that could use electric guitar

so this is Kokushibo he is cold, emotionless, and loyal to his master (Muzan)