Fisher's of Men (5E)

From publisher blurb: Fishers of Men is a 6th-level adventure that takes the characters into the Dragonmarsh Lowlands, a forsaken land blighted by the vile demon lord Tsathogga and countless foul denizens. When Quaywright Fishery inexplicably falls silent, it takes those of stout heart to determine what dire fate befell the former inhabitants and what monstrosity now lords in their place. The grisly carnage leaves even the most seasoned adventurers shaken to the core, as they witness firsthand and may personally experience what it feels like when the tables turn against humanity.