Without giving away too much, they're kind of the "baddies" of the game so they will feature.
We understand that people expect Chaos to be in the game and Chaos will be in the game, regardless of whether you prepurchased the DLC or not.
During my visit at Paris Games Week, I've had the chance to speak with Richard Aldridge (Games Designer at The Creative Assembly) about Total War: Warhammer, the strategy game set for release on April 28, 2016.