Ruins of the Old Empire
The Eladrin are the descendants of elves taken as slaves by the duergar. They proved a problem when the wars against the humans and free elves turned against their masters, as their freedom was one of the stipulations of the peace treaty but they had no way to live outside of duergar control.
In the end, they were given two great dwarfish citadels, Eilerinn and Odhosa, as their own. With help from a generation of human savants they built new lives. Their burgeoning magical connection to faerie world, an outgrowth of the peculiar religion they developed while underground, have driven them in directions very different from both the elves who are their brothers in body and the duergar who built their homes.