Phylactery

A phylactery is a repository used to store the souls of liches. A lich regenerates where its phylactery is located if its physical body has been destroyed. If the phylactery in question is destroyed, however, the lich ceases to exist. For this reason, liches seek to guard their phylacteries powerfully against attack. A phylactery can be a number of things, such as a sword, staff, or even a crystal.