The Chaos Warriors Add-on for Total War: WARHAMMER has 7 achievements.
Construct a Ruinous Warhost in one of your hordes.
Construct 5 Pillars of Skulls across your hordes.
Have at least 10 Chaos Knights in a single army.
Win a campaign as Chaos.
Playing as Chaos, research 8 technologies.
Playing as Chaos, research 16 technologies.
Playing as Chaos, research 24 technologies.