Decades ago, the Great Forest was plagued by a rash of sorcerous banditry. A coven of wizards made their hideout among the ancient trees and perpetrated a string of horrible murders. They kidnapped people from surrounding villages and sacrificed them to the horned god, presumably in exchange for magical power. Several members of this conspiracy were found and killed in a critical battle beneath the Inland Cliffs, but the sheriff could find little trace of the others, once their crimes had been discovered.
They have disappeared, but of course they have not been idle. The detritus of their activities is scattered all across the outskirts of civilization. The souls of those they murder in the name of the horned god are raised a year and a day later in the form of animalistic humanoids. Each of the Murdered bears a suffocating, horned mask, the instrument of their death, which the wizards remove before abandoning the corpse. The shaggy body grows out of this mask, and the new creature becomes a monstrous beast.
The last vestige of humanity left in the Murdered is their tendency to decorate their masks. The rest of their behaviour is savage and belligerent. Sometimes the wizards abandon them to their fate when they must leave an area quickly, but other times they use them as guardians of specific locations — for the Murdered will never attack the ones who killed them. Any other humans are fair game, however — for once they have risen from the grave, the Murdered becomes the murderer!