Centuries ago, before the Dark Elves were banished from Toril, they viciously attacked a High Elf City.
Unable to stand up to the Military might of the Drow, they sent out a call for help. But none of their elven allies came to their aid - in fact that's the one thing that the ghost elves have never forgotten. Eventually, help came in the form of a man named Thule.
~Thule offered to save them from the Dark elves in return for their service. The leaders of the city, appalled by the slaughter of their people, agreed without a second thought.
~Thule then revealed himself to be a pit friend of almost God - like powers & whisked the elves to his home in the Nine Hell of Baator. For centuries, the ghost elves served as slaves to the devils - working or fighting in cruel arena's battles. Their time in a foreign plane, cut off from the elf bond with the land, and almost completely destroyed their spirits -
~Their appearance also change giving them a glowing white skin and their eyes turned almost mirror- like. Eventually a ghost elf leader struck a deal with some demons of the hells, and there was a couple...in which the ghost elves made their escape through a series of portals, eventually ending backup in the material plane.
They have made enemies of the devils of the planes though, who seek out and hunt Ghost Elves whenever the opportunity is there-
Currently, Ghost Elves have no known home.