In the past, the Astartes could still be united around The Emperor and the Primarchs. Now, as the Imperium's most powerful military force, there was little anyone could do to stop a Chapter determined to turn against the Imperium except the Chapter itself.
Space Marine Chapters maintained a harsh, religious monastic system internally. First, to prevent Chaos corruption; second, to keep the Astartes under the Imperium's control through self-discipline.
If they lost the restraints of strict discipline and faith, and the Astartes began thinking for themselves, they would become no different from Huron.
First they fought for the Imperium, then for victory, and finally for the Chapter—for themselves.
Just as the Imperial Inquisition often said, "Thought breeds heresy."
If the Astartes stopped reciting convoluted, obscure scriptures of The Emperor and instead had the time and energy to consider such matters as the weakness and foolishness of mortals, how easily Chaos corrupted them, and how those in higher positions were even more corrupt...
Then the Imperium's next large-scale civil war would not be far off. After all, Horus had once held such thoughts. At least judging by Perturabo's situation, he would definitely help Huron deal the Imperial forces a vicious blow.
"Alright, alright, stop smashing things. We still have work to do. Let's settle the matter on this planet first."
Lin Fan told Perturabo to calm down, then took a bolt round to the head.
Fuming, Perturabo ordered Yvraine to restrain the Lamenters before they began preparing to deal with the unrest on the planet.
The planet's suffering was also easy enough to resolve. The horrifying scenes created by the Drukhari raiding party had left everyone trembling in corners. Hardly anyone dared risk being taken by the Drukhari to cause trouble in the hive city.
Several Aeldari disguised themselves as priests