Wellll... didn't I explain Herrscher already? Basically beings powered by honkai. Entropy. We were supposed to destroy humans, but there's some of us that are... uh. Either melded with them? Or just don't wanna destroy humanity anymore for our own reasons.

[ It is very complicated, so this is the super simple version. ]

And a divine key is just that. It means I have my own body and I can also go intangible if I really want! Or... could. Anyway. I dunno about here.