The Butcher

Somewhere in Slaughterswamp, the party attracted some kind of invisible creature. It first bumped up against their boat as they drifted across a lake of corpses, but was deterred when Echo made a loud noise. Later that night it reappeared, trying to drag Tek away from the party's campsite and towards the water. While the party managed to defeat it before it could drown him, it would not be the last time that Tek was assailed by someone or something that he could not see.
It's hard to say if the creature really was destroyed that night, and if the nightmare Tek had was simply a residual haunting or a sign of something worse. While they were fighting it, it seemed to interact with its environment almost as if it was a sentient gust of wind, but its lasting effects and proximity to the lake of corpses suggest there may be an element of the undeath involved as well.