The Dawn Isles
Religion and the Spirit Realm
I like that that in D&D they make a giant list of gods, including stuff like greek and norse mythology, and then lets you choose. So I started thinking about how there could be so many gods in one space.
For our world, I don’t think there’s any one creator god, or even any “greater gods”, but rather a wide collection of deities that affect the physical world in their own unique way. A lot of the tales about them include them descending from the heavens, the stars or the spirit realm, and walking among the mortals for a time.
But there are definitely still religions that claim their god to be the one and only, the maker, the light bringer, and so on. These will often denounce or even attack representatives of other gods. Similarly, there are single gods that have many different names in different regions and churches, and some religions that are made up by a charlatan or a cultist.
This is more than your characters will know, but I think all the gods were at one point mortals, but their strong spirit, power or presence has been brought over to the spirit realm, letting them affect our world and individual people in it.
For example, Moradin is described as the god that created dwarves. What if he actually was not a god, but the first dwarf to unite them as a people and found their society? Through the respect and power he commanded in his life, the stories about him that grew and grew, and peoples prayers, Moradin is now a powerful deity, capable of answering prayers, and empowering clerics, paladins and warlocks.
With a set-up like this, you are free to choose any of the suggested gods in the player’s handbook, or to make one of your own.
The planar system of D&D is wayyy to complicated, so I’m suggesting we only have a normal realm and a spirit (“fey”) realm. Celestial gods, sprits/fey and ancient beings and demons all exist in this plane, but spread out in their own locations.