I am planning on making a lich for an upcoming campaign and I want to do something creative with its phylactery. However, the rules on the phylactery don't tell me if merely damaging it affects the lich, or if destroying part of it (say, a third or half of it) effectively renders it useless. How has anyone called this in the past?
For specifics, my lich will be at the top of an extremely old, magical tower that changes its number of floors and monsters every time the characters enter it. The lich is intended to be an NPC who can give the characters any crucial information they desire every time they make it to the top, and though it isn't meant as an enemy itself, some characters (such as paladins) may fight it if they don't come to terms with the idea of a helpful lich. When thinking up its phylactery, it seems best that it should be the tower itself since it is already incredibly magical and strong, though if busting part of a wall in or destroying a floor in a magical blast or a strong storm destroys its use as a phylactery, then it obviously wouldn't work. I double checked that a phylactery does not actually need to be a small or tiny item, and can in fact be practically anything.
