The Gnoll Hunter is pretty rare. I have killed 6 of them and received 3 top staffs but 0 bottom staffs. They seem to spawn near the crossroads (North to Surefall Glade, east to West Karana), although I have never caught their initial spawn. Then they walk north over the hills on the east side of the road (the side that Blackburrow is on). One /loc is 2550, -144, 30. I have seen gnoll scouts, gnoll pups, and other mobs (rats, etc) on a similar path. I have yet to find the exact placeholder.
I can say that Holly Windstalker does not like gnolls and she will attack and kill this guy. She killed the Gnoll Hunter while I was following him and I noticed too late to secure the kill. Back to tracking...