"Born of ill means, though not of ill measure." -Rorrin Quellisar.
In ancient times, before the The First Snows, a party of adventurers known as The Dusk Blades encountered Xin Yue, the Spirit of the Dark, who tempted them with the promise of reward for committing increasingly foul deeds, which culminated in them being corrupted, becoming the ancestors of the Dark Races. These races have not had an ancestral home, being a minority in other societies.