The entirety of Baator had suffered horrible damage after the events that took place over the Styx River. Not only did the Chaos-Order Unity Formation devour a significant amount of its origin, but the Chaos Sphere that clashed outside Minarous, the Third Circle of Hell, wreaked havoc on its Crystal Wall.
After beating the Champion of Chaos like a dog, the Incarnation of Death and Destruction destroyed all the Rank 9 Archfiends. Even though the Archdevils managed to reform their bodies during the last century, none of them was at full power.
The only silver lining for the Archfiends was that the Primarchs had also suffered severe wounds during the battle, and none of them was ready to start an incursion into the Evil Planes anytime soon.
Unfortunately, someone healed much faster and was ready to go all out in Avernus.
