Much like the writing community, power metal is about half original content of varying creativity and about half fanfiction of existing content, mythology, or history.
Hey, kids, want to never have writer's block in your fantasy novel again? Well, listen, power metal will change your life. Real talk. Shit's great. I can't completely describe it, other than that it's everything I ever wanted out of music. It's literally the fantasy adventure genre of music, and I can't believe no one told me sooner. Let me try to sell you.