Dracolich

More than a powerful form of undead, a dracolich is a dragon who has voluntarily tied its soul to a phylactery, freeing itself from death. A type of lich, the creature's spirit can possess any dead serpentine body, usually their original form, and retain all the powers and abilities of the former body. That means a dracolich has the  supernatural fear aura, spells, and breath weapon it had in life, plus the terrible might of the undead. "

Becoming a dracolich
The process of becoming a dracolich was discovered by Sammaster the Mad, a fallen Chosen of Mystra, who was inspired after re-translating The Chronicle of Things to Come by the prophet Maglas. He was convinced that Toril would suffer a great apocalypse and "naught will be left save shuttered thrones with no rulers. But the dead dragons shall rule the world entire..." Sammaster's first success was with the great red wyrm Shargrailar the Dark in the Year of Queen's Tears (902 DR). Since then Sammaster and his followers, the Cult of the Dragon, have created many more, preparing for the apocalypse they "know" will come."

A dracolich has the strange ability to inhabit the body of any reptilian corpse upon death, though they are at their most powerful when inhabiting the corpse of a dragon. When killed in its corporeal body, the dracolich doesn't "die". Its spirit flees and hides in the phylactery, awaiting another suitable body to animate and inhabit. Like other types of lich, a dracolich is truly annihilated when its phylactery is destroyed.

Known Dracoliches

 * Aghazstamn
 * Alasklerbanbastos
 * Alglaudyx
 * Aurgloroasa
 * Cypress
 * Daurgothoth
 * Dretchroyaster
 * Hephaestus
 * Iltharaph
 * Kistarianth
 * Malygris
 * Rauglothgor
 * Shargrailar
 * Urshula
 * Vix'thra