@Nightfury Blizzard OK, that's one way of killing them but that only works when they are alone or weak or being attacked by someone who is vastly more powerful than them. Clearly, immortals can have children so even if they are being hunted there ought to be quite a lot of them. Additionally, if they kill each other, their power should be enormous, far greater than anyone else. An immoral slaying sword seems super rare and not something that most people would have access to so it still doesn't make a lot of sense.