As a consequence of the primordials victory, the Gray envelopes Athas cutting off the flow of souls to the realms of the gods. But there was one temple village devoted to a good god whose followers fought against the armies of the Champions of Rajaat; they were distraught at the thought of never achieving an afterlife but dissolving into nothingness. The followers were hopeful that their gods lack of communication doesn't mean their god is dead, but just cut off and will contact them again some day. Know that waiting for their god to return, every day their souls would dissolve into the Gray when they died, they perform an epic ritual that would defy the fate the Gray so that they would be there when their god returned.
As a consequence of the ritual, upon death, any soul a person from this temple village would avoid the Gray and instead reincarnate at a site holy to their faith. With the ritual in place, none of the affected followers can have children. With each reincarnation, memories of their past become dimmer and dimmer.
Calling themselves devas, today, their numbers had ever been few, and fewer yet have any remaining memory of where the original temple village was or if any devas still live there. After centuries of reincarnations, most devas consider themselves trapped in an unending cycle, cursed by memories of a naïve past that couldn't have imagined living in a world they are doomed to live in today. Many are resentful of their past, the decisions of those who doomed them to this eternal life, and resentful of those who are not cursed to relive life on Athas over and over.
While some devas have been broken and follow paths like defiling, seeking to destroy everything they can grasp, other devas have overcome the overwhelming burden of their memories and pursue paths of druidism to caretake the planet for future reincarnations.