Phylactery

A phylactery (or jar ) was the name given to the repository used to store the life force of lich. A cleric or mage had to create such a phylactery in order to become a lich,      and it was necessary for the lich to maintain its undead state and escaped being destroyed. Phylacteries were also employed by dracoliches and demiliches. Every phylactery was unique, in nature, defense, and means of destruction.

Creation
Making a phylactery was a highly expensive and taxing effort, requiring a high degree of spellcasting ability and total materials valued at 100,000 to 120,000 gp. While any object could be chosen to be the lich's jar or phylactery, it must be made of a solid material (and not wood) and be of high-quality craftsmanship. It could be non-magical or already be a magical item. It must cost no less than 2000 gp or much more, at several thousands of gold pieces according to maker's spellcasting power.

First, a prospective lich must cast the spell enchant an item on the object. If this worked, this was followed by trap the soul. If it was successfully made receptive to a soul, the would-be lich cast magic jar on the object, thereby making it the phylactery. Permanency and reincarnation could also be required.

Then the lich's soul entered the jar for the first time, but this exhausting process caused a loss of life-force and might, as well as erasure of their most powered prepared spells. Once their soul and vitality were successfully stored in the jar, then could leave and rest for at least a few days to recover.

Creation of the phylactery took a tenday to achieve. Only after it was complete could the lich commence the deadly ritual to full achieve lichdom.

Powers
Even before becoming fully a lich, the jar was of benefit to its still-living creator. If they died by any cause, their soul returned to the jar, regardless of how far way or what obstacles were before it, but it lost life-force and power once again. They could then reemerge and possess any dead body in the vicinity, whether their own, another's, an animal's, or an outsider's, becoming something like a wight.

If a lich's physical body was destroyed, it could regenerate itself where its phylactery was located within a tenday, with a new body appearing adjacent to it. However, if the phylactery itself was destroyed, then the lich could not regenerate and would remain destroyed.

To sustain the power of the phylactery and their undead existence, a lich needed to fuel it with the souls of others. They used the imprisonment spell to trap the soul of a victim within the phylactery; it would be held there for a full day before being consumed entirely unless freed with a dispel magic. A lich that did not trap souls in the phylactery regularly risked decaying physically and ultimately becoming a demilich.

Therefore, to guarantee destruction of a lich, it was necessary to destroy both body and phylactery. However, destroying the phylactery was difficult and usually a special item, weapon, or ritual was needed. A lich who survived the destruction of their phylactery could create a replacement.

Defenses
For this reason, liches sought to guard their phylacteries thoroughly against any attack and to place them in a secure and secret location. Typically, they chose hidden and well-defended vaults, even on other planes.

However, as a lich needed to be able to come and go from the jar and have spare bodies to inhabit, it needed to be in some accessible location; one that was too well-hidden might see them trapped. A lich's jar could not be found by locate an object, unless enacted by a god and only then the range was limited to the same plane and a distance of.

Description
Typically, a lich's phylactery was a sealed metal box, from the size of a fist to wide. Inside of this were strips of parchment bearing magical phrases and sigils written in silver; these were the spells of naming and binding, dark magic, and immortality that maintained the lich's existence. However, a phylactery could be any number of things, such as a ring or amulet, provided it had an interior space in which such writings could be placed. Other possibilities were a gem or even a totem doll.

Rumors & Legends
It was claimed that the demon lord Orcus, the patron of liches, could immediately obliterate the phylactery of any lich he was displeased with.

Background
Phylactery, from Ancient Greek (via Latin) for "protectant", is a term for a charm or amulet, a Christian reliquary, or a translation of the Jewish tefillah. It is also the term for "speech scrolls" in Medieval art.

In D&D, a phylactery was first mentioned in relation to a lich in the 1-edition Monster Manual (1977), but from this it is not clear what a phylactery is or why it is necessary. In 1979, "Blueprint For A Lich" in Dragon #26 first detailed the process of achieving lichdom, but referred instead to a "jar"; it's not clear if this is meant to be the same as the phylactery or not. The jar concept takes after numerous legends and stories of mages and villains who store their souls, hearts, or life in some object in order to cheat death. According to research by Buzz, here, it wasn't until the Endless Quest gamebook Lair of the Lich (1985) that the phylactery was linked to the soul-jar concept. Since then, the term "phylactery" seems to have become generally associated with liches and soul jars, both within D&D and across fantasy fiction. It wasn't until the 3-edition Monster Manual (2000) that the lich's phylactery was described in terms inspired by the various real-world phylacteries.

In D&D, the term "phylactery" is also used for various magical items worn on the head associated with morale and alignment.