A preface to something…
What are demons to your game world?
- Representatives of an absolute, objective evil (Hellblazer)
- Ancient races who walked the earth aeons ago (Buffy)
- Extra-planar beings separated from our world by a metaphysical barrier (Moorcock/Stormbringer)
- A breach in consensus reality (Sorcerer)
- A manifestation of personal power or psyche (also Sorcerer, early Stormbringer RPG)
That list moves from objective to subjective; in the middle point you get some kind of hand-waving “other dimensions, too numerous to count, fluid reality” explanation.
Consider two axes — on one you move between an objective and consensus reality to a subjective one, and on the other you move between summoning (and bargaining with) something other to conjuring something from the self. For example:
Until next time.