The Solar Auxilia march to Horus' banner!

"I am Mankind's only hope to prosper!"
– Warmaster Horus

When the Horus Heresy unfolded, the Imperium of Mankind was torn apart. Even though a large part of the Imperial Army remained loyal to the Emperor, there were those who saw the Warmaster as the herald of a new era.

As Horus advanced towards Terra, entire Cohorts swore fealty to the Warmaster and joined his ranks, forming the bulk of his forces. The moment is ever closer, and the traitor components of the Imperial Army are ready to join the battlefield in the upcoming expansion: Shadow of the Warmaster!