Yep. That Ordo Malleus
Don't know if someone already speculated on this, but I'm thinking that Grey Knights would be a great edition to Black Crusade. So much so, that rules for them might be in there. I mean, who better as an enemy of chaos? Right?
I know the book is dedicated to chaos. But meh, who knows. Could pull a fast one on us.
Discuss amongst yourselves.