A long time ago (we talking millions of years people) everyone had the prediction that soon the mythical beasts/creatures/symbols would all be personified. Predictions? Correct. Living together is a facility? Yep. Hotel? Trivago.
Powers: NO OMNI< MEGA< ABSOLUTE<TRANSCENDENT<ETC (Just don't make them OP)
Rules for what you can be: Zodiac Signs, Symbols used in mythology, Mythological creatures, Demons (of all kind except for Satan), and Fallen angels.
Rules for what you can't be: As said, not Satan and NO GODS/GODDESSES