For the reward, I would have expected a much easier quest than this.
You are literally taken into the bowels of Darkness Falls to kill a creature known as Lecherous Gress. He's in a dead end room that's south of the rocots, down the stairs & in back. For you Alb players this room resembles the "Cook's Room" on Alb's side of DF.
At level 37 you can duo this quest with a warrior and shaman like I did. There's lots of agro but if you can clear a path to the Lecherous Gress he's an easy kill. Resting areas to recharge health and power are almost non existant so be prepared to be on the move around the room. OJ & reds in this room to a 37.
Shaman doing the same quest was sent to Uppland to a gelitanous mass of some kind instead of the Lecherous Gress.