The Metagods combined to create the world of Diverion out of nothingness
Time before the gods disappeared
A war erupted between the Good deities and the Evil deities, over supremacy of the planet
Rudderless, the servants of the gods have done the best they can to carry on. The most powerful divine servants can still run the magical machinery that powers spells for their clerics, but only in a limited way. Entire libraries of knowledge were lost in the war, often buried intentionally to keep it out of the hands of enemies. Society has rebuilt itself out of the ashes of the war without their divine leaders. Celestials stepped up to run kingdoms and city-states in place of their gods. While immortal, over time, many of them were destroyed in battles with dragons, demons, undead, and the like, or succumbed to the Rivening, a kind of agony of separation from their deity, but some do remain. Some denizens of the Underworld did manage to hide on the surface to bide their time until they could move to take over a kingdom, city, or territory. Some openly rule while others manipulate rightful rulership through machinations and puppet strings.