Deep beneath the earth, the derro wait in twisted cities built by their mad architects. These insane humanoids live, work, and somehow thrive in the lightless depths. They understand the truth about the uncaring gods that dwell between the stars, and they abandoned sanity long ago to save themselves. The derro hide within their insanity in the hope that the dark gods they fear will turn that sinister attention to other, saner races first.

Despite the great distances between their underground cities and the surface, derro outposts can be found in the slums of many cities, both above and below ground. Occasionally, a derro discovers the wider world and finds a path out of the madness.

Playing A Derro

Derro are unpredictable, fanciful, and prone to delusions, confusions, and manias. So how can they function in groups more accustomed to the stability of humans, dwarves, and elves? In truth, the derro are less violent and more peculiar in a quieter way than their common portrayal as rabid maniacs.

They are as likely to be brooding, depressed, or sullen as crazed and violent. Your derro character could have a tendency to talk to themselves, might address an invisible friend before undertaking any major step, or might simply consider all the other members of the party as “imaginary friends” and thus not subject to harassment.

Treat the derro’s madness as an occasional bit of flavor for the character, rather than an excuse to cripple the party with chaotic and self-defeating actions. A derro character won’t be as predictable as a dwarf paladin or a half-elf bard, but the derro might occasionally talk to rocks and interrogate mushrooms. Review the Minor Madnesses section on page 22 for examples of playable and flavorful maladies that afflict your character. Choose an appropriate minor madness or roll percentile dice to randomly determine it. Your character should have at least one minor madness, but check with your GM to confirm how many and which minor madnesses are most appropriate in your campaign.

To avoid derailing the party constantly, your character can have long lucid periods and might even regret actions taken when “turned to the dark void” or “ridden by the bat spirits” or a similar explanation. A derro in this lucid state could be a tragic character, always wondering when something will set off another bout of irrational raving. Keep in mind, derro are often awed by beings they see as powerful, though each derro defines what they deem as “powerful.” Your derro character could view another member of the group as the group’s “witch queen” (regardless of that character’s gender) and follow that character almost zealously. The instability of the derro could also lead your character to choose a different member of the group each day or each week as the current “witch queen.” Playing a derro character involves making a fantasy form of otherworldly madness both playable and plausible. Find a way to make your character memorable without bogging down play or spoiling everyone else’s game.

Pale and Stunted

The derro are stunted, dwarflike humanoids, small of stature with wide shoulders and stubby limbs.

They stand between 3 and 4 feet tall, with males only slighter taller than females on average. Their slender builds rarely weigh more than 40 pounds. Their pale skin is nearly translucent, revealing a ghostly web of blue veins. Their large, pure white staring eyes gleam in the dark.

Shorter than surface dwarves, derro are quick and erratic in their movements. Their elaborately braided or styled hair ranges from white to a pale straw color.

Males take great pride in their prodigious mustaches, which are often braided and waxed.

History of Madness

The true history of the derro is an incomprehensible tangle. The entire race embraced insanity long ago. Even when they keep records, their accounts conflict with each other and with observable reality.

The various cults and clans of the derro embrace a wide variety of myths, mostly passed along by oral tradition and mind-bending artwork. Every new teller of a given tale twists or rewrites portions of the story to fit their own warped view of the world.

The derro have existed for ages, perhaps thriving even before the spread of humans across the surface.

The more reliable histories of other races agree the derro were once allied with the drow. The drow regard them with a strange type of favor, almost like dim-witted children. The aboleths and duergar have historically used and abused the derro. The derro know no actual friends, but they are overawed by power and dominance. They serve beings whose assumed superiority impresses them, and, when led in this way, their insanity clears enough to keep them moving toward the leader’s goals.

Culture and Rule

Love, as other races know it, is unheard of in the bizarre core family unit of the derro. Derro children are born sane, but they are deliberately driven mad by their relatives, usually by age four. Parents feed, clothe, and protect their children not out of a sense of love or tenderness, but because they know that every derro awakened to the mind-bending truth of their race brings them glory. The horrific rituals that break a young derro’s sanity vary by tribe and even year to year. Details are sparse, but known ritual names include Staring into the Void, Enduring the Heartless Fire, and the First Drink of True Knowledge.

Derro are paranoid, unstable, and jittery, and many suffer powerful delusions of grandeur as well.

Madness compels them to commit acts of cruelty against their companions or pets, and these acts ignite constant infighting among them. A few, however, muster enough restraint and control to keep the entirety of derro society from crumbling.

Savants are powerful sorcerers who hold their madness at bay long enough to cobble together coherent plans, though even they are dangerously unpredictable. The derro’s antipaladins are terrifying engines of crazed destruction who have looked deep into the void between stars and survived—and even the savants respect them for that. Clans that stick together long enough inadvertently create a witch queen among their ranks, a collective spirit of the clan. These derro become the leaders and central focuses of their clans, driving the clan to inscrutable ends. When one witch queen dies, her spirit transfers to another derro in the clan, transforming that derro into the next witch queen and perpetuating the clan.

Gods of the Derro

The derro worship a horde of bizarre and terrible beings, including demon lords. Perhaps the most disturbing of their deities are the Great Old Ones whose mere symbolic presence melts minds and corrupts the world. Derro worshipers venerate Nyarlathotep and Shub-Niggurath, the Black Goat of the Woods, in particular. There is no pattern or reason that governs which dark being will catch a given derro’s fancy, and devotees are violently hostile to worshipers of other entities.

Derro consider themselves the most exalted servants of the blasphemous figures they venerate; the only beings in the entire multiverse who can truly understand their deity’s glory. Specific rituals vary from cult to cult, but the unifying thread of derro faith asserts that their racial madness is a gift that makes communion with these deities possible.

Further, the derro believe they are the harbingers of the end of time and that they alone will inherit the shattered husk of creation.

Minor Madnesses
d% Effect
01–10 Collector; roll on subtable_1 for specific object
11–20 Pica (eats nonfood objects); roll on subtable_1 for specific object
21–40 Minor delusion; roll on subtable_3
41–50 Irrational prejudice against creature; roll on subtable_2 for specific creature
51–60 Taboo (cannot touch or interact with creature); roll on subtable_2 for specific creature
61–70 Phobia (strong fear of creature); roll on subtable_2 for specific creature
71–80 Obsessed with creature; roll on subtable_2 for specific creature
81–00 Physical effect; roll on subtable_4

Derro Names

Names are thrust upon derro children haphazardly and with no clear general customs. Derro who worship an ancestor god might give their children a variation on the exalted figure’s name or title, or a child might grow almost to maturity before any adult bothers to call them by the same jumble of sounds twice. Clan, tribe, and family names also lack any discernable pattern, though occasionally they form a coherent description.

Male Names: Akrath, Avrik, Brosh’Kal, Byrgryg, Crok’Til, Cyzyk, Daagrath, Durvin, Farq’shul, Folvig, Gaargrth, Grolesh, Haaskrin, Hvorig, Korzh, Lormaq, Orvuld, Ostvyrk, Perk’rasz, Pulver’Kash, Quirth, Qvaalak, Saasqar, Vorqaar.

Female Names: Aazha, Artriss, Bruen, Bylir, Dal’lyn, Drussil, Ealla, Erkytl, Grunhaas, Gvarla, Heldraag, Hylala, Muerna, Mzish, Ophella, Ortys, Rushal, Synder, Thryka, Tonlix, Ulga, Veraka, Vilya, Wulfada, Xanka

Tribe Names: Aardsyn, Blackreach, Balerock, Crystaaq, Daash’Void, Guundhold, Hellsreach, Iirdvank, Laash’Kath, Moldheim, Nyar’Ryk, Ovildhaash, Rylstaaq, Slys’Kath, Xaalyf.

Derro Traits

Your derro character has certain characteristics in common with all other derro.

Ability Score Increase. Your Dexterity score increases by 2.

Age. Derro reach maturity by the age of 15 and live to be around 75.

Size. Derro stand between 3 and 4 feet tall with slender limbs and wide shoulders. Your size is Small.

Alignment. The derro’s naturally unhinged minds are nearly always chaotic, and many, but not all, are evil.

Speed. Derro are fast for their size. Your base walking speed is 30 feet.

Superior Darkvision. Accustomed to life underground, you can see in dim light within 120 feet of you as if it were bright light, and in darkness as if it were dim light. You can’t discern color in darkness, only shades of gray.

Eldritch Resilience. You have advantage on Constitution saving throws against spells.

Sunlight Sensitivity. You have disadvantage on attack rolls and on Wisdom (Perception) checks that rely on sight when you, the target of your attack, or whatever you are trying to perceive is in direct sunlight.

Languages. You can speak, read, and write Dwarvish and your choice of Common or Undercommon.

Subrace. Three subraces of derro exist: far-touched, mutated, and uncorrupted. Choose one of these subraces.

Derro Subraces

Derro differ based on their location within derro communities, their clan’s connections to the dark powers that sculpt and manipulate the derro race, and the manifestations of the changes their otherworldly patrons bestow on them. Most derro dwell happily and deeply in their culture-induced insanity for their entire existence, others escape the madness-inducing indoctrination, and others still go straight through the madness toward powers beyond what derro usually enjoy.


You grew up firmly ensconced in the mad traditions of the derro, your mind touched by the raw majesty and power of your society’s otherworldly deities. Your abilities in other areas have made you more than a typical derro, of course. But no matter how well-trained and skilled you get in other magical or martial arts, the voices of your gods forever reverberate in your ears, driving you forward to do great or terrible things.

Ability Score Increase. Your Charisma score increases by 1.

Insanity. You have advantage on saving throws against being charmed or frightened. In addition, you can read and understand Void Speech, but you can speak only a few words of the dangerous and maddening language—the words necessary for using the spells in your Mad Fervor trait.

Mad Fervor. The driving force behind your insanity has blessed you with a measure of its power. You know the vicious mockery cantrip. When you reach 3rd level, you can cast the enthrall spell with this trait, and starting at 5th level, you can cast the fear spell with it. Once you cast a non-cantrip spell with this trait, you can’t do so again until you finish a long rest. Charisma is your spellcasting ability for these spells. If you are using Deep Magic for 5th Edition, these spells are instead crushing curse, maddening whispers, and alone, respectively.


Most derro go through the process of indoctrination into their society and come out of it with visions and delusion, paranoia and mania. You, on the other hand, were not affected as much mentally as you were physically. The connection to the dark deities of your people made you stronger and gave you a physical manifestation of their gift that other derro look upon with envy and awe.

Ability Score Increase. Your Strength score increases by 1.

Athletic Training. You have proficiency in the Athletics skill, and you are proficient with two martial weapons of your choice.

Otherworldly Influence. Your close connection to the strange powers that your people worship has mutated your form. Choose one of the following:

  • Alien Appendage. You have a tentacle-like growth on your body. This tentacle is a natural melee weapon, which you can use to make unarmed strikes. When you hit with it, your tentacle deals bludgeoning damage equal to 1d4 + your Strength modifier, instead of the bludgeoning damage normal for an unarmed strike. This tentacle has a reach of 5 feet and can lift a number of pounds equal to double your Strength score. The tentacle can’t wield weapons or shields or perform tasks that require manual precision, such as performing the somatic components of a spell, but it can perform simple tasks, such as opening an unlocked door or container, stowing or retrieving an object, or pouring the contents out of a vial.
  • Tainted Blood. Your blood is tainted by your connection with otherworldly entities. When you take piercing or slashing damage, you can use your reaction to force your blood to spray out of the wound. You and each creature within 5 feet of you take necrotic damage equal to your level. Once you use this trait, you can’t use it again until you finish a short or long rest.
  • Tenebrous Flesh. Your skin is rubbery and tenebrous, granting you a +1 bonus to your Armor Class.


Someone in your past failed to do their job of driving you to the brink of insanity. It might have been a doting parent that decided to buck tradition. It might have been a touched seer who had visions of your future without the connections to the mad gods your people serve. It might have been a whole outcast community of derro rebels who refused to serve the madness of your ancestors. Whatever happened in your past, you are quite sane—or at least quite sane for a derro.

Ability Score Increase. Your Wisdom score increases by 1.

Extra Language. You can speak, read, and write one extra language of your choice.

Psychic Barrier. Your time among your less sane brethren has inured you to their madness. You have resistance to psychic damage, and you have advantage on ability checks and saving throws made against effects that inflict insanity, such as spells like contact other plane and symbol, and effects that cause short-term, long-term, or indefinite madness.

Studied Insight. You are skilled at discerning other creature’s motives and intentions. You have proficiency in the Insight skill, and, if you study a creature for at least 1 minute, you have advantage on any initiative checks in combat against that creature for the next hour.

Subtable 1: Small Objects
d% Example
01–10 Rocks or crystals
11–20 Bones, hair, nails, or bugs (dead or alive)
21–30 Deodands (items responsible for the death of a creature)
31–40 Eyes, fingers, teeth, ears, toes, or other small body parts
41–50 Dirt, dust, or clay
51–60 Rags, cloths, or papers
61–70 Hats, socks, gloves, or other clothing
71–80 String, wire, or chain
81–90 Clockwork parts, jewelry, or buttons
91–00 Holy symbols, religious goods, or sacred texts
Subtable 2: Living Creatures
d% Example
01–10 Tiny insect, slug, or worm
11–20 Chicken, cat, dog, sheep, cow, or other domestic animal (pick a type)
21–30 Elf, dwarf, human, kobold, or other humanoid
31–40 Rat, giant centipede, gelatinous cube, or other giant vermin or ooze (pick a type)
41–50 Cleric or druid
51–60 Wizard or sorcerer
61–70 Sparrow, pigeon, hawk, owl, or other bird
71–80 Rat, wolf, mole, badger, or other mammalian beast
81–90 Construct or clockwork creature
91–00 Angel or fiend (pick type)
Subtable 3: Delusions
d% Example
01–10 Has imaginary friend; god/spirit who is friendly and encouraging
11–20 Has imaginary friend; god/spirit who is hateful and discouraging
21–30 Is a high noble of derro society
31–40 Has less power than actually does
41–50 Has more power than actually does
51–60 Has an important destiny
61–70 Believes a particular inanimate object (roll on Subtable 1) is alive
71–80 Is a powerful creature polymorphed as a derro
81–90 Is commanded by voices speaking random gibberish and commands
91–00 Random patterns of either inanimate objects (Subtable 1) or living things (Subtable 2) have an important meaning and must be studied
Subtable 4: Physical Effects
d% Example
01–10 Leers and rolls eyes upon seeing a particular type of creature (roll on subtable_2)
11–20 Tic or tremor in body part
21–30 Mutters constantly to self, sometimes narrating actions or feelings
31–40 Speaks inappropriate but true facts during diplomatic situations
41–50 Randomly speaks a word (chosen by GM) during combat or negotiation
51–60 Laughs at inappropriate moments
61–70 Weeps at inappropriate moments
71–80 Constantly clenches and unclenches hands
81–90 Minor hunchback
91–00 Half of face paralyzed
Section 15: Copyright Notice

Tome of Heroes ©2022 Open Design LLC; Authors: Celeste Conowitch, Jeff Lee, Sarah Madsen, Ben McFarland, Kelly Pawlik, Brian Suskind

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