There have always been small pockets of Twilight's Hammer cultists here and there, but never have I seen them in such numbers. They seem emboldened by someone, or something, to expand their influence. I would know more of these cultists and what they seek. Their shadowmancers are blessed by the dark powers and are likely the most trusted within their order to lead attacks of this scale. Bring me anything you find off their corpses that we may glean knowledge into their campaign.