The Banished Gods

The Banished Gods were stripped of their Identity near the End of the Purge War by Garn Zoren. Using means as yet unknown he reduced them to mere shadows and confined them to The Shadowfell. There they wait and scheme and plan, able to interact with the other planes only through servants and puppets. Even their names have been erased. What is known of their former selves is as follows:

The entire Yuan-Ti Pantheon that survived the onslaught of the other Gods were banished, the snake like entities are, in old records from before the Purge War, Listed as some of the most vile schemers across all the planes, enough so that even the Devils of the Hells refused to interact with them.

An unamed Bugbear who had ascended to Divinity and led his most devout followers to the southern continent in the hopes of allying with the Yuan Gods.

A group of former cultists turned gods through the decaying Divine Spring. They had once followed "The Elder Gods" but when they reached divinity of their own they began to wish for the destruction of their former masters.

These entities now form a collective and together they are the Banished. They will often taunt or bribe capable mortals through dreams or fantasies, promising the mortals riches or other rewards before hollowing them out so that only a shell that appears as the former mortal remains. There is no known way to reverse this effect.
The goal of the Banished is to return in their full power to enact their revenge, though the means to do this seems uncertain. PErhaps by destabilizing the planes they may be able to force their return or were they to expose themselves to the light of the upper planes, such as that that exists within Aasimar or other Angelkin.
Their most recent servant Ari Ashdew is certainly causing chaos as he has murdered important figures across The Material Plane, with a specific focus on those attempting to stave off war. Though his most recent attempt failed when he was interupted by Vinalmo Efrezi, One of the Dukes of Moromel.