I'm constructing a pantheon / theology for a fantasy world, and I'm a little stuck on a particular aspect. Here's generally what I have so far:
There are three planes - one 'light', one 'dark', and the material plane. There are 10 gods in the pantheon, each comprising a positive or negative aspect of an idea (gods for war and peace, light and dark, wealth and poverty, etc). The gods are not inherently 'good' or 'evil', they just rule over separate aspects of the ideals. Aeyr, the God of Life, did not see things this way. He sought to rule over the Pantheon that life and light and peace might dominate the planes, with him as supreme ruler. Begdreus, the God of Death, sees Aeyr's powerplay as a threat to the balance that the Pantheon represents, and moves to oppose him. This kicks off a great war between the Gods. The 'dark' gods are close to victory (having the God of War on your side helps in this regard) when Aeyr, desparate to acheive his vision, performs an act that separates the planes from each other such that there is no longer any overlap between them, thus stranding the Pantheon on their separate planes, and stranding their Angels on the material plane. The Angels can be influenced by the gods that created them, but otherwise have no direct communication to the other planes.
Fast forward an indeterminate amount of time (1000 or more years). The only angels remaining are those bound to the 'light' gods... but I'm not really sure why at the moment.
I've considered a sort of battle between the light and dark angels following the separation of the planes, but that feels a bit clunky. Ultimately where I want to end up is with the 'light' gods able to influence their angels, but for the 'dark' gods to have no means whatsoever to interact with the material plane. I thought about having some sort of treaty between the two sides, but the mechanics of the world would then allow the 'dark' gods to have the same kind of limited communication with their angels that the 'light' ones have with theirs, and I want to avoid that.
If it helps, there is still inherent magic on the material plane from the time when it overlapped the 'light' and 'dark' planes, though its magnitude has waned somewhat in the time since.