I just opened up a new area that's mostly Black Forest and a little Swamp. It seemed like it wasn't quite night yet but 2 Wraiths came out of the Swamp while I was definitely in the BF. On top of that I've not found any structures as this piece of swamp is like a thin ribbon with BF on both sides. A couple of game days later at night I got accosted by 2 more Wraiths at the same time. Hello bellows!

imo the Wraith's sound effect is too much like some sort of bleating farm animal lol