okay so, i just got my hidden appearance yesterday from Cemetery near felbane camp in HIGHMOUNTAIN, there has been past speculation on what is needed to be able to make the 5 heads to start dropping, i can confirm you do not need exhalted in any faction for them to drop, the artifact knowledge i am at AK8, so i would assume 4+, it took me about 2 and a half hours of farming in the same area for them all to drop alone with the skin itself, i can help with any questions on this subject if need be. because i know people were confused about the faction requirement , which bummed me out too, because i hate grinding faction rep