The Pact of The Primordials

Primordials asserted to the Old Ones, that the prime plane of the Material realm was theirs, as it was broken from their plane. They contested that the Divine should keep to Feywild and Astral And ethereal plane, the Devils and Demons Shadowfell,, and prime plane should be for the Primordials.

To this the Old Ones agreed, much to dismay of the Divine and mortal kind. While some of the elemental and primordials were decent enough to the mortals they ruled, a vast majority suffered, and entire civilizations were dismantled for these new Gods.
  Now the Divine were forced to select a few among the mortals to come with them to the celestial planes. Apollyon was also forced to remove his influence of Shadowfell, and abandon his Tieflings, and they turned to the Devils and demons now sanctified in their ownership.
  The Old Ones allowed the divine that dwell in the Feywild to continue unabated, for they had new designs upon the upper realms.