So, we know with the ending of WKM, Damien became a demon and that his focus is revenge for what happened to himself and Wilford.
Ok, so he’s a vengeance demon.
For those of you who don’t know, that’s a particular class of demons in the Buffyverse. They prefer to be called “justice demons,” but their job is exactly what it sounds like. Altering reality and creating scenarios where the person who calls on them can get a chance to change things, or to punish the person who hurt them.
And they all have a particular shtick: Anyanka’s was going to bat for women who had been scorned. Halfrek punished those who neglected or abused children. Malice provided closure for the dying.
But wait, it gets better.
Vengeance demons? They were humans who were turned into demons, due to some magickal influence.
But wait! It gets even better!
Do you know how they exact vengeance for their clientèle? The only way they can successfully access ALL of their demonic power?
So when Dark/Damien says he can give you (the viewer) anything? He’s not kidding… and he might just need you to wish for it.