As an incredibly powerful, mostly evil, very attractive supernatural being, I have one weakness:
A female protagonist who has just turned sixteen and thinks there’s nothing special about her at all.
Don’t worry, protagonist. I’m sure your ridiculously specific amnesia has nothing to do with the missing member of the royal family who is exactly your age.
For main female characters, prom is inevitable. Even if you try to skip it, a perfectly-fitting dress will appear in your life.
Lock the doors, or run far away. No matter where you go, prom will find you.