User blog comment:Vivaporius/AT Idea: Imperial Civil War/@comment-3341288-20120407183217/@comment-3258762-20120407184059

While the GK are brainwashed to be loyal, they seem to be some more to the Ecclesiarchy than the Emperor. And since the GK are better than regular Astartes, they will almost certainly use it in case they assault Terra.

And, as you know, Terra is the home of the men in gold. The super-soldiers of the super-soldiers, the Unseen Sentinels, the Invisible Guardians. The Adeptus Custodes! *Epic music*

Oh god. I just got a thought. A fight with 1 Custode vs 1 GK...to the music Dragon Rider!