We've seen the Twilight's Hammer cultists performing rituals to summon powerful elemental nobles. We don't know if these are the beings the cultists worship or if they act as intermediaries to even more powerful forces. One thing is for sure: they are receiving orders from these elementals.
I want you to find a way to contact an Abyssal Templar and give it a proper beating! Nothing throws the troops in disarray like taking out the chain of command. Bring back proof while you're at it.