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Type Humanoid
CR 3
Environment Underground

Source: Pathfinder Bestiary, pg(s). 70

From their homes in the Darklands, the insane derro spread fear and terror across the surface of Golarion.[1]


Derro appear like some demented form of short folk (standing three foot high), either halfling or gnome, that have been twisted into a horrible new form. Their skin is a pale, sickly bluish color, while their hair and milky eyes are pure white in color. Their eyes bulge from their head, giving them a frantic appearance. Because of their height and small frame, derros tend to weigh around seventy pounds. The derro's hands are odd, in that they only have four fingers, rather than five more commonly found in other humanoid races. These hands often wield one of the derro's unique weapons, most commonly the aklys.[2]

Habitat & Ecology[]

The derro dwell in the benighted depths of the Darklands, although only in the highest level of Nar-Voth. There they gather in insane communities dedicated to their race's eternal quest to walk in the world above. These enclaves are normally small and scattered across Nar-Voth. The notable exceptions are the larger derro populations found in the Nar-Voth cities of Corgunbier, Krba and Kmlin-Bru. Derro enclaves are always located beneath a large human surface settlement. Almost every city on the face of Golarion has a derro enclave hidden somewhere below it.[3] The derro seem to be mysteriously drawn to the heavily populated areas above. How this happens is a mystery, but why it happens is not: big cities are a perfect hunting ground for the derro, who kidnap and abduct without notice. While the vast numbers of a city's inhabitants may assist it in fending off an orc horde or other invading army, it actually makes people more vulnerable to the insidious threat of the derro. Despite how far they have spread due to their secretive nature, very few people know of the derro's existence.[4]

The derro have a very unique ecology that has developed from both their unique heritage (see history below) and millennia of adapting to their harsh Nar-Voth home. The evolution of their ecology is listed in the history section below and it has resulted in some strange features. Apart from their unusual appearance and psychotic temperament, the derro's most unique feature is their inability to tolerate sunlight. While artificial light causes some discomfort (unsurprising for a subterranean species), actual sunlight kills derro. Within an hour of exposure their skin is covered in blisters and within a couple of days they are nothing but a festering mass of bloody scabs, burnt flesh and bones. Some have noticed how similar this is to radiation burns.[5]

The derro have a strange life cycle. Their consumption of poisonous fungus means that derro have an unusually high amount of stillbirths, although their young reach full maturity by age nine. Derro females are able to give birth until far later in their life, which helps offset the high number of stillbirths. Still, the effects of their environment are not only negative; they have unlocked some unknown mental and magical potential which have lead to their leader wielding fearsome magical abilities.[6]


Derro society is obsessed with the world above, the so-called "Overburn". They wish to conquer its soft inhabitants, in order to harvest their endless resources. Unfortunately, they are limited in this endeavor by their inability to tolerate sunlight. The drive to overcome this weakness is the drive behind derro society. Small derro communities dot the length and breadth of Nar-Voth, which allows them to harvest test subjects from across the world without drawing attention to themselves. The derro realize how few their numbers are in comparison to the Overburn's inhabitants and so are careful about whom they take. They harvest their subject from the dregs of the largest settlements, people who won't be missed in a place too big to miss them. The derro then subject these victims to all manner of horrific experiments, trying to learn what it is that the surface races have that allow them to survive beneath the sun. These experiments range from skin grafts to trying to create their sunlight allergies in surface dwellers.[5] Some of these experiments have nothing to do with the race's goals and are just an excuse for individual derro to vent their sadistic urges on a sentient creature. Once they are done with their subjects, those that survive and are not driven utterly insane by the pain, are often released back onto the surface, after having their minds wiped by memory altering drugs. Unfortunately for their victims, this technique is far from perfect and they often retain vague memories of their experiences: monstrous pale creatures, glowing blue tunnels and unbelievable pain.[6] Other strange phenomena can also be attributed to the derro, in particular livestock mutilations. These are the results of derro either gathering exotic surface meat, or just venting their sadistic fury on a non-sentient victim.[5][7]

Relations with other Darklands races[]

The derro do not just limit themselves to capturing Overburn inhabitants and also abduct Darklands denizens like troglodytes and duergar. Darklands dwellers are a lot more aware and wary of the creepy derro and are thus less easy to capture. Those whom the derro do capture, are subject to the same hideous experiments, but they are never released afterward. Instead, they normally end up as an exotic dinner for the derro.

Compared to their fellow Darklanders, the derro are isolationists, keeping away from larger and more fecund races like the duergar and the drow. Despite their isolationism, derro enclaves often contain other Darklands creatures kept as slaves. The most common slaves are morlocks and mongrelmen as the derro find their flesh inedible.[7]


While not particularly religious creatures, when they do chose to worship, their gods are as unpleasant and sadistic as they are. Their pantheon includes the Mother of Monsters, Lamashtu, Andirifkhu, demon lord of knives and razors, Cyth-V'sug, lord of fungus, the demon lord of necromancy, Orcus and the sadistic Shax.[6]


Ironically, the most sadistic and evil race of the Darklands highest level were once the least evil dwellers of the deepest vaults of Orv. In ancient times, the race that would one day become the derro were known as the pech. These were fey creatures who had migrated from the mysterious First World, but also had an incredibly strong connection with the Elemental Plane of Earth. The tiny pech were servants to the mysterious creators of the Orvian Vaults, known as the Vault Keepers. Under the Vault Keepers, the pech helped to create and maintain the Vaults, but for some reason now lost to memory, the Vault Keepers fled from their creations, leaving the pech to fend for themselves.[4]

Thus abandoned, the pech fought amongst themselves, their bloody infighting eventually driving some to leave, seeking a better life in the tunnels above. As they strayed from the deepest vaults, the pech began to lose their connection to the First World much like the gnomes above. As they began losing this connection, they became more susceptible to starvation and thirst within the barren tunnels. As they ventured further into the barren caves above, their connections weakened and as they slowly starved , many went insane. They encountered what would become their salvation and their damnation: a strange, blue, glowing fungus that was highly nutritious called Cytillesh, more commonly known as brain mold.[4] Ingestion or long term exposure to cytillesh fungus spores is known to cause brain damage and a high rate of stillbirths.[8] Cytillesh became a central part of their society. To this day, every derro enclave contains a large patch of Cytillesh. The combination of their maddening exodus, their loss of connection to their home plane and the mutating effects of Cytillesh, caused the pech to become something completely different.[4] The derro grew in size from the pech, their limbs more elongated, their skin became pale, grey and leathery, while in their now sadistic and insane minds no trace of the benevolent pech remained.[4] All this happened in the ancient past, as even the most ancient of orc carvings and dwarven texts mention the derro. In fact, the completion of the dwarven Quest for Sky allowed the derro to spread into the tunnels now abandoned by the warring orcs and dwarves.[3] Nowadays, the derro have grown so used to the horrific effects of cytillesh, that they actually benefit from it. The fungus spores grant some of the older derro weird abilities both magical and psionic.[6]