Most WoW player think about the Ethereals as"Space Mummy Goblins"which is true.They're built politically just like the Goblins with many different mini-corporations working independently of one another. The friendly side, The Consortium and the Protectorate,work with players to fight the Void and the Ethereum in Nagrand and Netherstorm.They are beings of pure energy and look like Voidwraiths without their magical wrappings.This allows them to travel through space easily.

This is the only spot in WotLK where you'll see our electro-mummy friends.They are beyond any other WoW race in regards to technology.Not only can they travel space easily but they built the massive eco-domes and have mastered teleportation.This is probably why we don't see them a lot anymore because of how out of place they are. Not to reference how they play such a small role in the overall story.They have bases in Nagrand and in Netherstorm and make appearances in a few instances, but they don't have much to do with The Burning Crusade or Illidan.This makes them more of a non-factor lorewise than anything else.