The best ending would be for him to kill himself tbh. There is no other true way to get revenge than to just rip yourself from her, god that would be funny
So I guess we're about to find out that she was a loser in middle school and he was nice to her once and she of course fell in love with him and she found out he liked idols so she worked hard to become one, etc. etc. but she's also fucked in the head and gets off on torturing the guy she likes.