Doppelgänger (Dungeons & Dragons)

Doppelgangers in Dungeons & Dragons
In the Dungeons & Dragons fantasy role-playing game, Doppelgangers are infamous for their shapeshifting abilities. In DnD, Doppelgangers are lazy but cunning creatures, who kill or dispose of people then assume their place. In their true form, Doppelgangers appear as tall, elfin, gray-skinned humanoids, whose thin bodies make them appear (to human eyes) sexless. A Doppelganger's metamorphic abilities have two flaws: they can only assume the form of a being of the same sex with any real effectivity and even then they can only mimic with 90% effectiveness.

Doppelgangers hate working, and so usually assume the forms of people who are well off in society, commonly working in groups so as to be able to replace the entire family and leave the servants working for them. Doppelgangers are believed to be an artificial race, created by some mad wizard, and to this day have a fondness for working with the magically inclined; mainly being used as assassins or in elaborate plots to usurpe power.

Doppelganger families tend not to be close; usually a male and female meet, engage in casual sex, then leave one another, with the female being forced to single-handedly rear any resulting newborn- who will leave their mother upon reaching maturity. Some Doppelgangers however form tight-knit family clusters, while others will mate with humanoids; taking malicious delight in using their non-Doppelganger husband or spouse as a cover for their inhumanity. Children born of such unions have a 50% chance of being either humanoid or Doppelganger.

Dread Doppelgangers
A subspecies of Doppelganger can be found in the Demiplane of Dread- Ravenloft. These Dread Doppelgangers, like many Ravenloftian creatures, are a twisted 'upgrade' of the normal Doppelganger. Dread Doppelgangers are capable of mimicking with 100% efficiency as well as generating natural illusions via their 'Glamer' ability, but in the process have become sexless parasites, dependent on their ability to integrate with society to survive. While normal Doppelgangers have their own culture and have no real need to mingle with humanoids, Dread Doppelgangers can only reproduce by mating with humanoids (usually doing so as males, as a 'pregnant' Dread Doppelganger cannot change forms until after giving birth) and have effectively lost their own culture.

Dread Doppelgangers have one major accomplishment over their natural kin: their own country. The Ravenloft domain of Paridon is the birthplace of the Dread Doppelganger, and as such is crawling with the vile things. The Darklord of the place; Sodo the Flickerflame, directs and organizes a vile ritual called the Blood Rite, which takes place once every thirteen years and is used by Sodo to give himself effective immortality. This ritual is conducted by a chosen Dread Doppelganger, and is referred to by the Paridoners as "The Bloody Jack Killings" due to the fact that for many years Paridon thought the killings were the work of a madman.