User blog comment:Vivaporius/AT Idea: Imperial Civil War/@comment-3341288-20120407183217/@comment-2253300-20120407192328

The Grey Knights do not serve the Ecclesiarchy. No way, no how. They are independent from all other Imperial organizations except the Ordo Malleus. Furthermore the Astartes are warriors of the Emperor, first and foremost. Having said that the Grey Knights would only be even more loyal to the Emperor. There is no way they would side with the Ministorum in this conflict.