|“||“Shapeshifters,” the Khelbens replied in unison... “Somehow they disposed of Lady Eidola's attendants and took their places. When I found them out, I led them back into the crying room for questioning. One of them attacked. They rushed for the door, taking my form to confuse pursuit.” “If I am a shapeshifter,” said the fifth, “why did I slay two of my comrades with a crushing hand?” The ninth shook his head. “He slew only those two, and in front of you so that you would believe him. I killed the rest”||”|
In their true form, doppelgangers appeared as tall, elven, gray-skinned humanoids, whose thin bodies made them appear, to human eyes, sexless. Even this form was deceptive, suggesting they were physically weak, when in fact they were quite strong and agile. The normal appearance of a doppelganger was that of a gray-skinned humanoid with a formless face and pale white bulging eyes with no visible pupils. They had no hair in their normal form.
They were lazy but cunning creatures, who killed or disposed of people then assumed their place. While not actually evil, doppelgangers were extremely self-centered and liable to look down on their victims.
Doppelgangers were feared for their ability to assume the form of any humanoid creature they encounter. Doppelgangers were used as spies and assassins by many beings all over the world.
Many doppelgangers lived a stolen life. When they encountered a person whose appearance or station they desired for themselves, the doppelganger used their mental powers to learn everything they could about the chosen target. Once they had all the knowledge they needed, they quietly eliminated their target and assumed his or her form, taking their place in life.
When a doppelganger was impersonating someone they sometimes kept the original alive and close for weeks, using their ability to read the victim's mind daily to learn how to behave and speak without being detected.
Doppelgangers could assume shapes of any humanoid creatures between 4 and 8 ft. in height. After they chose their victim they duplicated the victim's form, clothing, and equipment, and attempted to kill the original. The biggest boon for the doppelgangers was the confusion their shapeshifting caused. Oftentimes doppelgangers worked in groups to ensure their infiltrations' and attacks' success. Doppelgangers were immune to sleep and charm spells. 
Doppelgangers called their species the Shallar. Doppelganger families tended not to be close; usually, a male and female met, engaged in casual sex, then left one another, with the female being forced to single-handedly rear any resulting newborns—who left their mother upon reaching maturity. Some, however, formed tightly knit family clusters, while others mated with humanoids, taking malicious delight in using their spouse as a cover for their inhumanity. Children born of such unions had a chance of being a half-doppelganger.
In the Year of the Banner, 1368 DR, the trading company Seven Suns's headquarters in Baldur's Gate was infiltrated and taken over by doppelgangers, working on behalf of the rival organization Iron Throne. The doppelgangers then proceeded to make poor business decisions that drove the coster toward bankruptcy. This affected the economy of the whole city and attracted the attention of the Grand Dukes. Scar, the commander of Baldur's Gate's Flaming Fist mercenary guards, asked Gorion's Ward to investigate strange goings-on at the Seven Suns headquarters in Baldur's Gate. Gorion's Ward and their team eliminated the doppelgangers.
In 1377 DR, a group of doppelgangers infiltrated a wedding ceremony between Piergeiron the Paladinson and Eidola of Neverwinter in Waterdeep, posing as guards and handmaidens. Khelben "Blackstaff" Arunsun foiled the monsters' sinister plot but failed to stop Eidola's subsequent abduction.
- Bonnie, the leader of a doppelganger gang who worked as a barmaid in the Yawning Portal in the late 15th century DR.
- Hlaavin: the half-illithid leader of an autonomous druuth in Ch'Chitl.
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- Fraser Sherman (December 1983). “Ecology: The psychology of the Doppleganger”. In Kim Mohan ed. Dragon #80 (TSR, Inc.), pp. 6–8.
- Ed Greenwood, Eric L. Boyd, Darrin Drader (July 2004). Serpent Kingdoms. (Wizards of the Coast), p. 55. ISBN 0-7869-3277-5.
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Doug Stewart (June 1993). Monstrous Manual. (TSR, Inc), p. 60. ISBN 1-5607-6619-0.
- ↑ 2.0 2.1 2.2 2.3 Wizards RPG Team (2014). Monster Manual 5th edition. (Wizards of the Coast), p. 82. ISBN 978-0786965614.
- ↑ Mike Mearls, Stephen Schubert, James Wyatt (June 2008). Monster Manual 4th edition. (Wizards of the Coast), p. 71. ISBN 978-0-7869-4852-9.
- ↑ 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 4.11 4.12 4.13 4.14 4.15 Skip Williams, Jonathan Tweet, Monte Cook (July 2003). Monster Manual 3.5. (Wizards of the Coast), pp. 67–68. ISBN 0-7869-2893-X.
- ↑ 5.0 5.1 5.2 Ed Greenwood and Steven E. Schend (July 1994). City of Splendors. (TSR, Inc). ISBN 0-5607-6868-1.
- ↑ Gary Gygax (December 1977). Monster Manual, 1st edition. (TSR, Inc), p. 29. ISBN 0-9356-9600-8.
- ↑ 7.0 7.1 J. Robert King (February 1998). The Abduction. (Wizards of the Coast), p. 63. ISBN 0-7869-0864-5.
- ↑ Ed Greenwood (2013-01-04). Quelzard, Patron of Adventurers. Forging the Realms. Wizards of the Coast. Archived from the original on 2013-02-21. Retrieved on 2013-06-30.
- ↑ Wade Nudson (November 2003). “Strange Bedfellows: New Half-Monster Templates”. In Chris Thomasson ed. Dragon #313 (Paizo Publishing, LLC), p. 93.
- ↑ Ed Greenwood, Eric L. Boyd, Darrin Drader (July 2004). Serpent Kingdoms. (Wizards of the Coast), p. 55. ISBN 0-7869-3277-5.
- ↑ BioWare (December 1998). Designed by James Ohlen. Baldur's Gate. Black Isle Studios.
- ↑ Christopher Perkins, James Haeck, James Introcaso, Adam Lee, Matthew Sernett (September 2018). Waterdeep: Dragon Heist. Edited by Jeremy Crawford. (Wizards of the Coast), p. 20. ISBN 978-0-7869-6625-7.
- ↑ Steven E. Schend, Sean K. Reynolds and Eric L. Boyd (June 2000). Cloak & Dagger. (Wizards of the Coast), p. 143. ISBN 0-7869-1627-3.
- ↑ Steven E. Schend, Sean K. Reynolds and Eric L. Boyd (June 2000). Cloak & Dagger. (Wizards of the Coast), pp. 99–100. ISBN 0-7869-1627-3.