Tales of Tiamat

What will happen if a sadistic,training addict stunningly beatiful girl not-so human embarks on a journey to kill whatever has the misfortune to provoke her and become the stroest existence in the multiuniverse while having fun?

I don't own the image and this novel is a fanfiction of different novels and anime

This is my first novel so i'd be happy if you give some advice and there will be a lot of error because i'm not that good in English