Anyone who is not you. You can stab them, shoot them, burn them, and there are no consequences! They just blink for a couple of seconds and disappear. They're not very useful. They basically just regurgitate the same few lines over and over again and they charge to much gold for their wares! (You can craft better weapons and armor anyways:) and the best part is that once you hit lvl 30 all of the town guards are too weak to challenge you. Don't worry though, they don't feel anything. Essentially, semi-autominus husks. So slay await. Take what is yours.