So something I do with a lot of my characters is make them undead or ghostly. I have a lot of characters who are skeletons who refused to die, or spirits possessing the armor they wore in life. So what do I call this? They're not a zombie, as they maintain full mental capacity and free will. They aren't liches as they didn't do anything magical with the intent of unlife. I often refer to them as skeletons or ghosts but I don't think that fits either. Is there a name for this?