Propaganda.

Whilst rumors spread of lone individuals, squads, and in one case even a whole company of Primaris marines kneeling before the Dark Gods and swearing new allegiances across the bloody battlefields of the Imperium. War is already raging amongst the ranks of the Ordos Hereticus and Malleus. Doubters and believers alike exchange gunfire and lies daily as they desperately seek the their own versions of the truth... 
Reality?

Are Roboute Guilliman and Belisarius Cawl, both the Master and Commander of the Primaris marines, the saviors of the Imperium in these desperate times? Or, with the proliferation of their so-called monsters across the stars, are they in truth the architects of its total destruction? 

lol, I'll bet you didn't think I was going to take that initial query into this direction did you?