Askhalite

Most of the time an askhalite has no body of its own; it rides inside a host who looks entirely normal. When it reveals itself, the host's flesh reshapes into the creature's true form: bigger, broader and more heavily muscled than a man, with skin black as ebony, a heavy, knotted brow, and claws in place of fingernails. It speaks its own tongue plus every language its host knows.

Every one of these beings is tied to a single object, most often a medallion. Someone, typically another askhalite, must give it to an intelligent creature who accepts it freely. The recipient then saves vs. spell; failure means the bound askhalite takes over, steering the host like a puppet and using any of its mental powers through it.

The possessed host never lets the object out of its keeping. Remove it and the askhalite bursts into its true form and fights to win the object back. The host's body changes on the spot, taking on the askhalite's level, Hit Dice and attacks, much as if the creature had cast polymorph other or shapechange on it. The change also breaks any charm, beguiling or similar mental control on the host, including hold person, since the askhalite form does not count as a person. In true form it has strength comparable to an ogre's and still benefits from any magic the host had beyond that.

At will the askhalite can teleport or plane shift its host to wherever its object lies. It can also abandon a host, even making the host hand the object on to someone more powerful or useful.

Killing the true form kills the host, who reverts to its own shape as it dies; the object then goes dead and is safe to touch. Destroying the medallion while the askhalite occupies a host also kills the host, though nobody knows what that does to the creature itself. A dispel evil cast specifically to free a victim can drive the askhalite back into its object, but only if it beats the creature's magic resistance and the askhalite fails a save vs. spell.

Askhalites come from somewhere beyond this world, perhaps the same region as certain soul-trading merchants from outside it, and they are a hostile race bent on spreading their grip across other worlds. They serve a shadowy god-ruler, him or it, and their society is a theocracy where those who have done the most for the god stand nearest to it and are fittest to rule. Rumors of stronger askhalites with spells and extra powers remain unconfirmed.

For all their ambition they are cautious. If the general population discovers the plot, askhalites drop it and withdraw, releasing their hosts unharmed.

Sages guess the creatures are extradimensional and need their bound object to exist, or to remain, on this plane. Each object seems keyed to one askhalite; no captured medallion has ever answered a second creature after its original owner died.

While its askhalite is alive, even before anyone has accepted the gift, its object is nearly impossible to break. When the askhalite dies, the object loses every special property. The wisest sages know at least four medallion patterns, but whether they mark ranks or factions is a mystery, and the form of the item (ring, circlet, phylactery, gem pendant and so on) may carry its own meaning.