I saw this on Enworld: http://www.enworld.org/forum/content.php?2851-OU-OF-THE-ABYSS-Has-Derro-Check-Them-Out!#.Vd3U_flViko. I figure the Demon Lords are in a separate appendix (at least I hope they are).
Intersting - looks like they'll be early on, low-level antagonists. Interesting to see that it looks like their devilish heritage has been removed.
Also, Ixitxachitl! In my own campaign, the main antagonists are aquatic, so they'll fit perfectly. And I really want to know more about The Pudding King. A little bit of research shows he's a svirfneblin worshipper of Juiblex.
Interesting to see that it looks like their devilish heritage has been removed.
I thought it was the Duergar that had devilish heritage, not the Derro.
DemoMonkey wrote:
Whoops, brain must have misfired there.
In Forgotten Realms, the mind flayers did what the the Suel (humans) did in Greyhawk. 
DemoMonkey wrote:
In my settings, derros are sane, rational, most of time because cooperation is totally necesary to survive. Maybe they are mind-controlled by some creature, for example a brainstealer dragon or psionic pupetters, or they need a special drug, or it is caused by a contagious disease, like an infection (like the gore-horror apocalipse comic "Crossed", or a softe version of "28 days later").
Derros are perfect to be followers of a Lovecraftian cult, but I don´t like to imagine them too fool, because then they couldn´t survive, or even they would kill each other.
From that description, it looks like Derro and Duegars should just be the same thing. There isn't enough difference between them to warrant being considered different races.
Duergars are dwarf with psionic powers and very bad mood. Derros are dwarfs without good sense.
For me the derros are too fool to survive without tribe cooperation, but they are perfect to be (partially) mind-controlled slaves.
* Could derros by controlled by duergars with levels of the psionic prestige class "Thrallherd"?
Can we really be 100% sure they're actually derro and not just svirfneblin in white wigs?
Derro are also smaller then Duregar and honestly don't look too much like them other then being somewhat Dwarfish.
Derro look like Magic Kithkin but insain.
Derro are on-again off-again in terms of being dwarves, at that. In other ones they're more human
MonsterEnvy wrote:
Hebitsuikaza wrote:
Derro, from the 1e MM2 (pretty much copied and pasted from the adventure The Lost Caves of Tsocanth—where the originally appeared):
"The derro are a degenerate race of dwarf-like stature, possibly a cross between evil humans and dwarves. They inhabit the great subterranean realms common to drow and their ilk (kuo-toans, mind flayers, troglodytes, etc.). Although the derro hate light and suffer from nausea in sunlight, they venture out upon the surface of the earth at night through secret shaft openings to steal and kidnap humans for slaves. Rumor says that some humans are actually eaten as well."
"Derroes are very much like humans, only shorter and slightly more muscular in proportion to their height. Their features tend towards grossness. Their hair is pale tan or yellow, their skin is very white wtth a bluish undertone, and their eyes are very large."
In the Greyhawk setting, they are said to have been bred by the ancient Suel Empire from dwarves and humans.
In contrast, Duergar (again, from the 1e MM2—where they made their first appearance):
"The duergar are the seldom-encountered race of evil dwarves. They are also known as the gray dwarves or gray ones. Malicious in the extreme, duergar dwell in subterranean depths where their evil need not withstand the light. Normally but a handful of these wicked creatures will be discovered, but occasionally a lair will be discovered with hundreds of duergar there."
"Duergar appear as emaciated, evil-visaged dwarves Their skin is medium to dark gray. They favor garb of drab color, typically that which blends into their environment. They live longer than do normal dwarves, some reaching 500 or more years of age."