Once a misguided and corrupted thief who has come back to serve the Raven Queen
Elomir Stormcrow was once the famed leader of a local band of mercenaries around Wellspring. He had been hired to travel to the Forlorn Tower to seize a powerful artifact of Ioun called The Tear of Knowledge. The tainted power of the the stone corrupted his mind, and he and his mutated allies sought to keep it for themselves.
His mind, and all hope for redemption, were lost when another group of thieves stole the Tear from him. That’s when the PCs encountered him and killed him and his aberrant lackeys to death.
But the Raven Queen was able to see his regret even though his soul was as nearly twisted as his mortal body had been. She saw a champion that would fight for his vindication as well as be a useful ally to her other champions.
Elomir was returned to the world as a revenant and encountered the heroes when they entered the Shadowfell to stop any plans to use the Tear.