Board Thread:Warhammer 40k General Discussion/@comment-6134883-20130417202949/@comment-6134883-20130424173008

Gentlemen let us keep in mind that the Brides of the Emperor fought Space Marines AND Custodes to a standstill in the battle of the Palace at the end of the Apostasy. Granted they probably were able to do so thanks to the advantage of being on the defensive but they did it. And it would seem that the Sisters of the Argent Shroud were a respectable threat to the Angels Vermillion.

Basically the Astartes represent brute strength and the Sisters agility and speed as well as faith. Clearly the forces compliment each other when they work together and equally clearly it is not always the Battle-Brother's fault when they fight each other instead. Sibling rivalry is the bane of the Imperium.