1. Descent into undeath
These lumbering, rotting corpses were once innocent townsfolk who have made the final transition into true undeath... They are vicious creatures, retaining little of their humanity. The plague has torn away most of their memories, leaving only hunger and basic survival instincts in their place... Even those who were close to the individual in life have difficulty recognizing their loved one; the transformation removes most vestiges of humanity as well as identifying features of voice and body structure.WoWWiki