Lich

These beings are powerful magic users that were once living humanoids of some type that have become obsessed with gaining immortality.
A mage becomes a lich by means of necromancy, using a magical receptacle called a Phylactery to store the lich's soul. In some sources the method of becoming a lich is referred to as the Ritual of Becoming or Ceremony of Endless Night. The process is often described as requiring the creation and consumption of a deadly potion, the Elixir of Defilation, which is to be drunk on a full moon; although the exact details of the potion are described differently in various sources, the creation of the potion almost universally entails acts of utter evil, such as using as an ingredient like the blood of an infant slain by the potential lich's own hand, or other, similarly vile components. The potion invariably kills the drinker but if the process is successful it rises again some days later as a Lich. Occasionally, this metamorphosis occurs by accident as a result of life-prolonging magic.

Unlike most other forms of undead creatures, the Lich retains all of the memories, personality, and abilities that it possessed in life — but it has a virtual eternity to hone its skills and inevitably becomes very powerful. Like other powerful forms of undead (such as a vampire), a Lich has unnatural powers owing to its state. For example, it can put mortals in a paralyzed state of hibernation with their minds, making them seem dead to others, and can through its typically powerful magical spells, summon other lesser undead to protect it. A Lich's bones do not decay. The Lich is capable of sustaining tremendous physical damage, and is immune to disease, poison, fatigue and other effects that affect only the living. However, despite all its undead "gifts", a lich's most valuable resources are its vast intellect, its supreme mastery of sorcery and limitless time to research, plot and scheme.

Since a lich's soul is mystically tied to its phylactery, destroying its body will not kill it. Rather, its soul will return to the phylactery, and its body will be recreated by the power keeping it immortal. Thus the only way to permanently destroy a lich is to destroy the phylactery as well. Therefore, the lich will generally be extremely protective of the priceless item. The phylactery, which can be of virtually any form (the default form is a metal box filled with rune-covered papers, but it usually appears as a valuable amulet or gemstone), will often be hidden in a secret place and protected by powerful spells, charms, monsters and/or other servants; the phylactery itself is usually of magical nature, meaning its destruction will generally be no easier than obtaining it.

Lifespan

Immortal