Fey

The Fey were the self styled guardians of the planes, and were led until very recently by their Queen, Lilliana. Some 800 years ago, the Fey were at war was Thrast, which, thanks to Telarus, they were able to win.
Recently however, Yeenoghu attacked the main fortress of the Fey with a shard, and reduced the whole place and everyone in it (Lilliana included) to atoms. How many fey and to what capacity they can still function is unknown.