|This article requires cleanup. Reason: The information presented here seems to contradict that in Mordenkeinen's Tome of Foes, someone please update this page to include the latest lore.
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Derro appeared to resemble small dwarves. They had blue-gray skin, and their hair was often white or yellow in color. They lacked both irises and pupils, showing uniformly pale eyes. Most derro looked haggard and wore shabby clothing, appearing pitiable to unsuspecting victims.
Derro were widespread and were likely to be found in small bands throughout the Underdark. Derro warrens existed in many drow and duergar cities, but they were almost always treated as a disrespected underclass. 
The derro were a strange and sadistic race. While clever and stealthy they were also murderously insane. It was very common for derro to devote themselves to some strange quest, such as collecting only certain types of gemstones or slaying as many members of a particular race as possible. Some derro were assigned specific missions by powerful derro savants, with the possibility that they might even join a company of comrades to fulfill some irrational goal. It should be noted that derro, despite their insanity, still retain the natural knack for inventiveness shown in dwarves. An example of this is the repeater crossbow, which the derro may have invented.
Derro bands survive the challenges of the Underdark only due to their intense paranoia and the sorcerous powers of their leaders. 
There are other conflicting legends of how the derro came to be. The duergar believe that the derro are another dwarf clan that was held long by mind flayers, which resulted in the madness that afflicts them. The derro themselves all tell oft-changing variations of the myth of Diirinka; all versions share a common focus on Diirinka's stealing magic from a great evil to help the derro survive through their ideals of deceipt and cruelty.
- Buppido, a cunning and insane killer who believed to be the incarnation of the derro god Diinkarazan.
- Realms of the Underdark: "The Fires of Narbondel"
- Condemnation (Mentioned only)
- Storm of the Dead
- Venom in Her Veins
- Video games
- Owen K.C. Stephens (March 2001). “By Any Other Name: Races of the Underdark”. In Dave Gross ed. Dragon #281 (Wizards of the Coast), pp. 46–49.
- ↑ 1.0 1.1 1.2 Christopher Perkins, Adam Lee, Richard Whitters (September 1, 2015). Out of the Abyss. Edited by Jeremy Crawford. (Wizards of the Coast), p. 224. ISBN 978-0-7869-6581-6.
- ↑ 2.0 2.1 Mike Mearls, Jeremy Crawford (May 29, 2018). Mordenkainen's Tome of Foes. Edited by Kim Mohan, Michele Carter. (Wizards of the Coast), pp. 158–159. ISBN 978-0786966240.
- ↑ 3.0 3.1 3.2 3.3 Skip Williams, Jonathan Tweet, Monte Cook (July 2003). Monster Manual 3.5. (Wizards of the Coast), p. 49. ISBN 0-7869-2893-X.
- ↑ Doug Stewart (June 1993). Monstrous Manual. (TSR, Inc), p. 96. ISBN 1-5607-6619-0.
- ↑ Eric L. Boyd, Erik Mona (May 2002). Faiths and Pantheons. (Wizards of the Coast), p. 221. ISBN 0-7869-2759-3.
- ↑ Frank Mentzer (January 1985). “Ay pronunseeAYshun gyd”. In Kim Mohan ed. Dragon #93 (TSR, Inc.), p. 26.
- ↑ Christopher Perkins, Adam Lee, Richard Whitters (September 1, 2015). Out of the Abyss. Edited by Jeremy Crawford. (Wizards of the Coast). ISBN 978-0-7869-6581-6.
- ↑ 8.0 8.1 8.2 Mike Mearls, Jeremy Crawford (May 29, 2018). Mordenkainen's Tome of Foes. Edited by Kim Mohan, Michele Carter. (Wizards of the Coast), pp. 1–256. ISBN 978-0786966240.
- ↑ Tim Pratt (March 2012). Venom in Her Veins (Kindle ed.). (Wizards of the Coast), loc. 2983. ISBN 0786959843.
- ↑ Tim Pratt (March 2012). Venom in Her Veins (Kindle ed.). (Wizards of the Coast), loc. 3216. ISBN 0786959843.
- ↑ Christopher Perkins, Adam Lee, Richard Whitters (September 1, 2015). Out of the Abyss. Edited by Jeremy Crawford. (Wizards of the Coast), p. 6. ISBN 978-0-7869-6581-6.