Tracking a Killer

Gor'krosh, the Long Knives, has been terrorizing the Valley of Trials for weeks. Orcs have been going missing, and many of our young trainees have been injured. The peons took to calling the mysterious attacker the Long Knives because the few bodies we have found all have long, terrible gashes across their backs. They're terrified, and refusing to work! We have no idea who or what Gor'krosh really is, but they are clearly very dangerous. Please, find this monster and end this madness!