Biological information
Type Aberration
Size Medium
Intelligence Psionic sentient
Life span -
Sociological information
Planet of origin -
Achieved warp -
First contact -

The illithid, also known as a mind flayer, is a hostile, spacefaring humanoid creature. Illithids are infamous for their grotesque eating habits, which involve grabbing prey with their tentacles, then tearing the prey's brains out to eat. Nowadays, however, they have created a sapient race called the oortlings to feed off. Cruel and sadistic, they often trade slaves.

Not allied with Daelkyr


The illithid, or mind flayer, is an evil and feared creature of the Underdark; its powers are formidable and it feeds on the brains of any creature it encounters. Using arcane powers, it enslaves or destroys its foes, which include such powerful creatures as drow.

Mind flayers stand about 6 feet tall and have hideous mauve skin that glistens with slime. The head resembles an octopus, with white eyes (no pupils are evident) and four tentacles around its mouth, a round, many-toothed orifice like that of a lamprey. The creature has three reddish fingers and a thumb on each hand.

Illithids have darkvision. They can communicate with any creatures via innate telepathy; they have no spoken language, although they often accompany their thoughts with hissing, and the eager lashing of their tentacles. Mind flayers dress in flowing robes, often with high, stiff collars, adorned with symbols of death and despair.


A mind flayer's preferred method of attack is the mind blast, projected in a cone 60 feet long, 5 feet wide at the mind flayer, and 20 feet wide at the opposite end. All within the cone must make a saving throw vs. wands or be stunned and unable to act for 3d4 rounds. The illithid tries to grab one or two stunned victims (requiring normal attack rolls if others try to prevent this) and escape with them.

The illithid keeps some victims as slaves and feeds on the brains of the others. When devouring the brain of a stunned victim, it inserts its tentacles into the victim’s skull and draws out its brain, killing the victim in one round. A mind flayer can also use its tentacles in combat; it does so only when surprised or when attacking a single, unarmed victim. A tentacle which hits causes 2 hp damage and holds the victim. A tentacle does no damage while holding, and can be removed with a successful bend bars/lift gates roll. Once all four tentacles have attached to the victim, the mind flayer has found a path to the brain and kills the victim in one round. If preferred, the DM can simply roll 1d4 for the number of rounds required to kill a struggling victim.

A mind flayer can also use the following arcane powers, one per round, as a 7th-level mage: suggestion, charm person, charm monster, ESP, levitate, astral projection, and plane shift. All saving throws against these powers are made at a -4, due to the creature's mental prowess.

If an encounter is going against a mind flayer, it will immediately flee, seeking to save itself regardless of its treasure or its fellows.


Mind flayers hate sunlight and avoid it when possible. They live in underground cities of 200 to 2,000 illithids, plus at least two slaves per illithid. All the slaves are under the effects of a charm person or charm monster, and obey their illithid masters without question.

The center of a community is its elder brain, a pool of briny fluid that contains the brains of the city’s dead mind flayers. Due to the mental powers of illithids, the elder brain is still sentient, and the telepathic union of its brains rules the community. The elder brain has a telepathic range of 2 to 5 miles, depending on its age and size. It does not attack, but telepathically warns the mind flayers of the presence of thinking creatures, so a mind flayer within its telepathic radius can be surprised only by non-intelligent creatures. The range of the elder brain determines the territory claimed and defended by the community, though raiding parties are sent far beyond this limit.

Mind flayers have no family structure. Their social activities include eating, communicating with the elder brain, and debating on the best tactics to conquer the Underdark. For amusement, they inflict pain on their captives and force slaves to fight in gladiatorial games.

Mind flayers are arrogant, viewing all other species only as cattle to be fed upon. They prefer to eat the brains of thinking creatures.

Mind flayer cities generally have more slaves than mind flayers. Slavery looks like their purpose of being in the material plane instead of dwelling in the astral plane and they are good at it. However, they got in some serious problems because of slavery once in their history, gith problem. The gith race, the original race of githyankis and githzerais, was a slave to illithids and one day they broke free which led the giths to be separated into two factions. However, giths became fearful enemies of Illithid race.


Mind Flayers don't have a religion as humans would recognise it, but they do have a deep reverence for certain concepts of the mind, such as knowledge, memory and aptitude.

The illithids' reverence and meditation on these ideals could be considered a form of worship.

Illithids strive for a mental state of perfect comprehension of knowledge, a simultaneous recall of memory, thought, and aptitude. They call this state of quasi-enlightenment Maanzecoria.


Mind flayers live about 125 years. They are warm-blooded amphibians, and spend the first 10 years of life as tadpoles, swimming in the elder-brain pool until they either die (which most do) or grow into adult illithids. On an irregular basis, adult illithids feed brains to the tadpoles, which do not molest the elder brain. Illithids are hermaphroditic; each can produce one tadpole twice in its life.

Slave races

Illithid Ships

The mind flayers used to have a spelljamming empire that spanned most, if not all of the crystal spheres,
The illithids are the first race to have a spelljamming empire,
Illithids are powerful, but they are really just the tools of the elder brains,
Gith smashed the mind flayer empire (and the githyanki and the githzerai hunt down and kill any illithids that attempt to reorganise),
Individual elder brains attempt to come up with plots that will allow them to reestablish their lost empire,
Nautiloids may be one of the oldest ship designs in the Spelljammer universe (the illithids may be the oldest race to learn how to spelljam),
Nobody knows how Gith destroyed the illithid empire. The mind flayers don't talk about it, the githyanki and githzerai don't talk about it and even the gods don't talk about it,
Gith's followers split into the two factions we know today after the illithid empire was destroyed,
Gith went to Hell (seems like they renamed the Nine Hells) to strike a deal with Tiamat, and never returned,
Vlaakith returned in Gith's place and told her followers that she had been sent to lead them until Gith returned,
Some red dragons have been ordered to help the githyanki.
The service that red dragons provide to the githyanki interfers with their usual ageing process, and therefore stops them growing into larger dragons (so this service is a big deal).

Half-Mindflayers (Quasiceremorphs)
Ceremorphosis was a bodily change that occurred when an illithid tadpole reached maturity and was inserted into the brain of another humanoid being, usually a human. The tadpole ate away the victim’s brain matter and essentially replaced the brain, erasing all of the subject’s personality and memory, but leaving the physical body alive and under the tadpole’s control. After this, “morphological transformations” occurred and after a week a new illithid was created.

It was common for the newly formed illithid to retain a few memories of its former host. Those memories were merely vestigial and rarely affected the new individual’s personality.

If this was done with a non-human, the result was called a “half-illithid”. Another name for a half-illithid was “ceremorph”. They did, however, still possess most of the powers of a regular illithid.

On rare occasions, something happens to humans during the ceremorphosis where the tadpole ate the brain but was not able to bring the human “to full term.” Typically, this happened as a result of the tadpoles carrying a rare illithid disease or coming from a weak brood. Usually, these “quasiceremorphs” are killed outright. However, some elder brains have seen value in this sub-species and their ability to blend in with humans.

Illithids (also called Mind Flayers) are so insidious, diabolical, and powerful that all denizens of space
fear them. They bend others to their will and shatter enemy’s minds.

An illithid is a strange creature, standing some 6 feet tall, that is humanoid only in the most general
terms. Its flesh is rubbery and mauve, glistening with chill slime. The creature’s head looks rather like
a four tentacled octopus, made all the more horrible by a pair of bloated, white yes. Its mouth, a
revolting thing like a lampreys maw, constantly drips an oily slime when it is not siphoning out the
brains of living prey.

In addition to being highly intelligent, wholly evil, and terribly sadistic, mind flayers are utterly selfserving.
If an encounter turns against the creature, it flees at once, caring nothing for the fate of its
companions and servitors. Illithid speak Undercomman, but prefer to communicate telepathically.

Illithid like to fight from a distance, using their psionic abilities, particularly their mind blast. If pressed
into melee combat, an Illithid lashes its enemies with the tentacles ringing its mouth.

Illithid congregate in domed cities, shielded from the sun of their home system. The centre of each
community is its Elder-brain, a pool of briny fluid that contains the brains of the cities dead Illithid.
Although they constantly vie for power, Illithids are quite willing to work together. A small group of
these creatures known as an inquisition, often forms to root out some dark and terrible secret. In
many ways, an Illithid inquisition is not unlike a party of adventurers, with each member contributing
its own skills and knowledge to the group. When a task is too great for an inquisition to handle,
Illithids generally form a cult. A pair of Illithids commands the group, each struggling for supremacy.
Exactly why no individual assumes leadership of a cult is unknown.

The Heart of Illithid space is their home system Stygia a system with seven planets, most barren and
barely able to sustain life. All the systems planets revolving around a dying sun, which provides little
light to the outlaying planets now. The whole of the Illithid civilisation is known as the Illithid Unity, a
collective society with each Elder Brain that communicate with each other acting as a larger racial

The Illithid have conquered many worlds, enslaving them to their purpose, serving as a labour force
but more often as a food source, the Illithid also prey on many species using them for slaves. They
are very cunning about this though, and do not hit any target for slaving purposes they cannot
handle, and are careful to leave no trace or witnesses to their activities, of course it is well known in
shadowy circles that slaves can be bought from the Illithid, but proving it is another matter entirely,
and none dare cross the Illithid as those that do often end up their next meal.

The Illithid build hidden installations where they re-supply and store slaves for transportation in
Astralspace, and their vessels are capable of moving into Astral space.

The Illithid Navy consists of three major vessel types The awesome Dreadnought, the powerful
Nautiloid and the sleek fast striking Boreworm. All are grown vessels and move under an unknown
means of propulsion.

shou-kkar are used as shock troops

The origins of the illithids has been described in several conflicting stories offered in various D&D products, in past editions and in the current version of the game, which can be taken as successive retcons.

The 2nd Edition book The Illithiad suggests they may be from the Far Realm, an incomprehensible plane completely alien to the known multiverse. There is no mention of time travel in this theory. Instead, they emerged somewhere countless thousands of years ago, beyond the histories of many mortal races, and spread from one world to another, and another, and so on. It is explicitly stated in this book that the illithids appear in some of the most ancient histories of the most ancient races, even those that have no mention of other races.

The 3.5 Edition D&D supplement Lords of Madness provides that the Illithid were a star-faring people who existed at the end of time. Facing annihilation, the Illithid traveled to the past, arriving roughly 2000 years before the present in any given D&D campaign.[16]

The 4th Edition preview Wizards Presents Worlds and Monsters supports the claim that mind flayers originate from the Far Realm.

In these two differing versions of the story, much of the variance hinges upon a fictional text called The Sargonne Prophecies. The Illithiad described the Prophecies as misnamed, and that much of it sounds more like ancient myth than prophecy. Lords of Madness takes the name more literally, and states that The Sargonne Prophecies are in fact prophecy—or, perhaps more accurately, a history of the future.

Yet another version came from The Astromundi Cluster, a Spelljammer boxed set produced before The Illithiad. This version holds that the illithids are descended from the outcasts of an ancient human society that ruled the now-shattered world called Astromundi. The outcast humans eventually mutated, deep underground, into the mind flayers. (This boxed set also introduced the entity known as Lugribossk, who was depicted as a god of the Astromundi flayers then, but was later retconned into a proxy of the god Ilsensine.) In the retconned history of the illithids found in either The Illithiad or Lords of Madness, the emergence of illithids in Astromundi becomes a freak occurrence due to the intervention of Ilsensine through its proxy, since the illithids of Astromundi have their own histories as emerging solely upon that world.

However and whenever it occurred, when the illithids arrived in the Material Plane of the far past, they immediately began to build an empire by enslaving many sentient creatures. They were very successful, and soon their worlds-spanning empire became the largest one the multiverse had ever seen. They had the power—in terms of psychic potency and the manpower of countless slaves—to fashion artificial worlds. One such world was this empire's capital, called Penumbra, a diskworld built around a star, which was a thousand years in the making. Such was their might that the Blood War paused as the demons and devils considered a truce to deal with the illithid empire.

Eventually, the primary slave race of the illithids developed resistance to the mental powers of their masters, and revolted. Led by the warrior Gith, the rebellion spread to all the illithids' worlds, and the empire collapsed. The illithid race itself seemed doomed.

Gith was betrayed by one of her own generals, Zerthimon, who believed she had grown tyrannical and over-aggressive. Civil war erupted, and the race factionalised into the githyanki and the githzerai (and in the Spelljammer campaign setting the Pirates of Gith).[29] This disruption allowed the illithids to retreat to underground strongholds where they still dwell.

Dungeon #100 claims the original home of the gith forerunners was a world known as Pharagos. Currently it is described as, "an unremarkable Material-Plane world, a far cry from the hotbed of magical activity and divine intervention that is the Forgotten Realms campaign or the World of Greyhawk." Beneath the Wasting Desert on that world, however, is the petrified corpse of the long-dead patron deity of the ancestors of the gith races. As is recounted in most 1st and 2nd edition sources, the ancestors of the gith forerunners were a human civilization before being modified by countless generations of illithid breeding and profane science.

The background material of the Chainmail game[30] places the gith forerunners in a subterranean empire called Zarum in Western Oerik, where they dominated many other races from their capital city of Anithor. These gith seem to have been divided into a rigid caste system, their lives ruled by ancient ritual. The ruins of Zarum overflow with sacred spaces and temples, though the names of the ancient gith gods are unknown today. The period of Zarum's height is not entirely clear, but grey elf sages speculate it was approximately 2,000 years before the Demon Wars that ravaged Western Oerik, or 3,000 years before the present.

At some point, the illithids invaded Zarum from a neighboring plane of existence. Though the gith fought fiercely, they were no match for the psionic might of the mind flayers, and soon they were enslaved. The River of Angry Souls is a remnant of one of the terrible battles between the illithids and the soon-to-be enslaved gith. Many were brought to the Outer Planes and elsewhere to serve as illithid slaves. Other cities in Zarum were transformed into work pits where illithid overseers forced their slaves to toil for countless generations.

After Gith's rebellion, she led her people to the Astral Plane. While a few subject races and surviving illithids remained on Oerth, the gith forerunners have departed the world, seemingly for good. If they retain any interest in the ruins of Zarum, it is well concealed. A portion of the ruins of Anithor were eventually colonized by the drow of House Kilsek, who named their new settlement Kalan-G'eld.

Of all questions surrounding illithids, “Where did they come
from?” is the most mysterious. For an answer to this riddle,
scholars are limited to scraps of clues from a handful of ancient
texts. The clearest reference is found in The Planetreader’s Primer,
a book of primeval knowledge published (reputedly) in the
great city at the center of all, Sigil. It speaks in certain terms
of an illithid empire that spanned worlds in a time predating
memory. So mighty was this empire that its expansion
threatened to consume even the eternal Blood War before it
was turned back.
The Astromundi Chronicles, a text of ancient yet unknown
origin, speaks of the illithids as “a race of monstrous spawn,
hidden beneath the world by their progenitors.” No clue is
given as to the identity of these progenitors. The text suggests
that the illithids hated their creators with such passion that
they lashed out against them and destroyed them utterly,
leaving no trace of their existence for the modern scholar to
The most archaic of all sources is a set of stone tablets known
as the Sargonne Prophecies, named for the city of disturbing
ruins called Sargonne. The crumbling tablets contain passages
so cryptic that they have been interpreted as prophecies rather
than as history. Each bears a central likeness of what is unmistakably
a mind fl ayer. The inscribed runes present a troubling
aspect to the observer. They tell of an illithid world “bathed in
eternal night” that is destroyed by some fi ery cataclysm, from
which the illithids fl ee in fl ying ships.

From these fragmentary glimpses into the dim past and
the oral histories of several long-lived races, scholars have
concocted the following “history” of the illithid race.
Its origin is simply unknown. Wherever they came from,
in time so ancient that no record of it exists, illithids ruled a
vast, worlds-spanning empire.
This empire, built on a foundation of slavery and domination
over whatever other races existed at that time, dwarfed
everything that has come since. At some point, certain of
those enslaved races developed a degree of resistance to the
psychic shackles of the illithids. When they had gathered
suffi cient power, the slaves revolted. How it was done no one
can say, but the slaves succeeded in toppling their masters and
winning free. The age that followed was one of unrelenting
revenge as desperate pockets of illithids were hunted and
The freed slaves were not free of strife, and they fell to
warring among themselves. This had two effects. First, the
feuding branches of ex-slaves became what are now known as
the githyanki and the githzerai, who make war on each other
to this day. Second, the illithids that eluded their vengeance
were able to regroup and escape to defensible fortresses
deep underground, where the gith races chose not to pursue
This account is basically true in its outline but is fl awed in
one astounding respect. While the rebellion of the gith did
indeed take place in the past—about two thousand years ago,
to be precise—their mind fl ayer masters had themselves just
arrived in that era from the unimaginable future.
At the very end of time, the mind fl ayers faced extinction at
the hands of some unknown adversary. Caught in the throes
of defeat, harried in their crumbling capitals and universities
(lesser outposts had fallen eons before), the surviving illithids
concocted a desperate plan. As their last bastions were
assailed and their psychic defenses breached, the mind fl ayers
sacrifi ced countless ancient, potent elder brains to produce a
psionic maelstrom of unimaginable proportions. The ensuing
cacophony of energy demolished the very laws that support
the structure of time. The illithids and all that remained of
their decadent civilization were hurled backward across the
ravaged barriers separating the ages to arrive in the present
world, but thousands of years ago, as recorded in the Sargonne
The illithids’ staggering gamble paid off. Upon arriving in
the human world of several thousand years past, they quickly
enslaved the humanoid race known as the gith, seeking to
reestablish their empire in their new age. After centuries of
servitude, the gith successfully rebelled against the mind
fl ayers. Much of the knowledge and wondrous magic brought
to the distant past from the illithid empire at the end of time
was destroyed in this rebellion, and for long years the mind
fl ayers were scattered and disorganized in its wake.
While the rebellion of the gith was a great catastrophe, the
mind fl ayers are a patient race. They need only wait in the darkness,
planning, correcting foreseen mistakes, and gathering
strength for the time when they return to ascendance.
In the impossibly far future, when stars are reduced to
pale, red cinders fl ickering coldly over somnolent worlds,
the illithids will rise from their subterranean dens to face the
languid twilight and establish once more the empire they lost.
They will be stronger, crueler, and hungrier than ever, and all
hope will die.

Illithid communities are fi lled with slaves or, more correctly,
thralls. Thralls do all menial work in illithid society. They are
the household servants, public workers, and draft animals.
They even fi ll the ranks of the mind fl ayer armies, where
their role is largely to serve as cannon fodder while powerful
illithids wreak havoc on the enemy with mind blasts and
mental domination.
Newly captured slaves are subjected to inspection and
disinfection, followed by constant psychic bombardment to
ensure that they become docile and willing thralls. Those
lucky few who managed to escape from thralldom describe
it as a waking nightmare. The slave is always aware of what
he is doing and is fi lled with revulsion at his deeds, but is
powerless to resist illithid commands. The hopelessness and
horror of this mental captivity bears down on the thrall as a
constant weight.
Many thralls are captured in raids, but not all. Some are
bred selectively for strength, docility, or even coloration or
Few thralls die of natural causes. Most become meals for
their masters. Their usefulness doesn’t end at death, either.
The bodies (minus the brains, of course) are fed back to
other thralls.
In addition to the tasks they perform, thralls provide
another service to their masters. Illithids have a need to
dominate lesser creatures and take great pride in the quantity
and quality of their own personal thralls. An illithid with an
especially valuable or exotic thrall enjoys great prestige among
its peers, while an illithid without thralls is considered weak
and incompetent.

In the short term, though, mind fl ayers work toward a few
recognizable goals.

  • They oppose and kill githyanki and githzerai wherever and whenever they locate them.
  • They establish links to nonillithids who can be of service to them while scouting others as potential targets for raids.
  • They seek to maintain a steady inf lux of brains for nourishment.
  • They expand their knowledge in every area. Only through knowledge can they make accurate predictions about the future.
  • They seek to undermine burgeoning empires on the surface. Illithids don’t see surface empires as direct threats to their eventual rise. Rather, they interfere with growing empires experimentally. In this, the whole surface world is their laboratory. By meddling in surface politics to bring about governmental collapse, mind fl ayers hope to learn what pitfalls to guard against when erecting their own empire.
  • The longest-range and most ambitious plan of all is to fi nd a means of extinguishing the sun. Mind fl ayers aren’t harmed by sunlight, but they hate it and avoid it at all costs. If the world could be plunged into darkness, the illithids could expand from their subterranean lairs onto the surface, where all the best brains are to be found.

Mind fl ayers gather knowledge in four ways: They purchase it
from traveling merchants, steal it directly from the minds of
traveling merchants, absorb it from the brains of their victims,
or read it from the minds of their captives. None of these
methods are ever used in isolation. More than any other race,
mind fl ayers are aware of the ways in which faulty perception
and personal interpretation can distort facts. They always seek
to verify important information with multiple sources.
Mind fl ayers are most interested in news about happenings
on the surface of the world, what the drow are plotting, anything
having to do with githyanki or githzerai, news involving
their own activities, and important astrological or magical
discoveries. They are interested in everything else, too, but
these subjects command their attention.

Few surface dwellers understand how and why mind fl ayers
involve themselves in the affairs of surface realms. Most would
be even more surprised to learn that the illithid infl uence is not
entirely negative. Mind fl ayers have been known to intervene
to prop up failing governments or aid weaker societies against
encroachment or invasion by someone stronger. Of course,
it’s impossible to aid one society in that way without acting
at another society’s expense, so “positive infl uence” depends
on the point of view. If a society is plunged into anarchy and
desolation to allow another to expand, the interference that
brought about that change of fortune can hardly be considered

Mind fl ayers fi nd it surprisingly easy to infl uence surface
politics, using their tremendous psionic ability to read and
implant thoughts. Their machinations are always behind the
scenes. They alter the mind of a king or queen directly when
that sovereign is strong, or they work through the minds
of advisers and sages when a monarch is weak-willed. The
reverse experiment is also a worthy exercise: infl uencing a
strong-willed monarch through his councilors, and adding
decisiveness and purpose to weak rulers.

The extent of this manipulation is impossible for surface
dwellers to judge. Few ever become aware of it, and they are
seldom in a position to do anything about it. In cases where a
seemingly healthy monarch or noble abruptly begins acting
in a way irreconcilable from his or her established beliefs, the
possible cause might lie beyond senility, madness, or demonic
possession. A wise court wizard would do well to guard his
sovereign against mental manipulation.

Contrary to what some believe, illithid motivation for meddling
in surface politics does not involve creating chaos or
instability for its own sake; that is mainly a side benefi t, from
their perspective. In truth, the elder brains seek to understand
the dynamics of the rise and fall of kingdoms, empires, and
civilizations. The history of their own, original rise from
obscurity to universal domination is lost to them—they don’t
know how they did it the fi rst time. Now that they have been
given a second opportunity, they intend to maximize their
chances of doing it right and making it last forever. To that end,
they want to explore every pitfall, every catastrophic decision,
and every nuance of rule, warfare, diplomacy, and governance
through surface proxies.

Despite all their unique and overwhelming abilities, the
mind flayers are a race on the edge of extinction.
Thousands of years ago, the illithids were the dominant
power of the Inner Planes. From their astral
domains, they launched flying vessels called nautiloids,
able to cross between planes, so that they could harvest
intelligent humanoids from hundreds of worlds.
The mind flayers relied on a slave race, the gith, to
provide physical labor and sustenance when other
sources of food grew thin. Eventually, the gith revolted.
Whether the mind flayers became decadent or the gith
discovered a weakness, none can say. What is known
is that after centuries of domination, the mind flayer
empire collapsed in less than a year. The gith rose up,
slaughtered their masters, and destroyed almost all
traces of the illithids' astral domains.
Only the mind flayers that had infiltrated the worlds of
the Material Plane survived, and their safety was shortlived.
Both the githzerai and the githyanki, two factions
that arose from the victorious gith, sent hunting parties
to root out and slaughter the remaining mind flayers.
To this day, isolated clutches of mind flayers remain
in hiding, seeking ways to recapture their former glory
but hampered by their paranoia of being discovered and
destroyed by their enemies.

Speculation persists concerning mind flayer realms yet
adrift in the Astral Plane. Though no one has discovered
such a place, it is beyond dispute that an empire as vast
as the illithids' built great cities and other edifices. Most
sages, however, believe that the gith tore apart every last
bit of mind flayer artifice, ensuring that no evidence remained
of the mind flayers' reign.

A few skeptics suggest that the entire narrative of the
gith victory rings false. How could a slave race overpower
the mind flayers? Where are the signs of this
great struggle? Perhaps the gith didn't actually win. Perhaps,
instead, the mind flayers moved themselves and
their works into the future to avoid being overrun. That
theory would explain the mind flayers' disappearance
and the absence of any ruins from their empire.
Few folk take such talk seriously, yet no one can be
sure exactly what the illithids are and are not capable of.

Sometimes a mind flayer that's away from its colony
breaks free from the elder brain. Perhaps it ran into a
situation where its bonds of obedience were broken, or
perhaps the colony was destroyed while it was away. In
such a case, the mind flayer becomes free-willed for as
long as it avoids contact with an elder brain.
A renegade illithid remains fearful of gith attacks,
and likely sets about creating a sort of colony of its own,
the better to remain undetected. It gathers minions,
establishes a lair, and makes defense of its territory a
top priority. Unlike colonial mind flayers, rogue illithids
develop a healthy respect for those not of their kind.
They treat especially powerful creatures and individuals
as equals, not adversaries, and seek to cooperate with
them. A renegade mind flayer might become a trusted
advisor or a powerful ally, so long as it is kept well fed.
Any alliance it makes, however, collapses if the mind
flayer falls under the sway of an elder brain once more.

The first priority of any mind flayer colony is to survive.
The elder brain and its servants seek to remain hidden,
typically deep within the earth, while harvesting enough
intelligent humanoids to nourish themselves and allow
for slow but steady growth.

Once a colony is secure, it focuses on the Grand
Design-the mind flayers' plan to rebuild their lost empire.
The illithids know that reclaiming their rightful
place in the world is possible only after the githzerai
and githyanki have been eliminated and the remaining
humanoids have been turned into docile slaves. To that
end, each colony conducts research into the nature of
the world and the creatures that inhabit it. The mind
flayers examine all facets of reality, seeking any knowledge
that could give them the edge they need to confront,
defeat, and subjugate their enemies.
Every colony investigates a wide variety of topics and
phenomena. A few members might focus on straightforward
projects such as developing new uses for psionic
power or how to breed savage creatures to serve as foot
soldiers. Others pursue more theoretical subjects. A
mind flayer might study musical tones, for example, in
hopes of finding a way to manipulate the emotions of
humanoids. Another might research the food humanoids
eat to see if their diet or agricultural practices can
be exploited. No line of inquiry is too esoteric if it might
provide the next step in enacting the Grand Design.

Since mind flayers need to settle near a source of food,
they must determine how best to interact with the humanoids
they intend to conquer. A colony usually adopts
one of three approaches to dealing with its neighbors.
Control. A colony that desperately needs to increase
its population concentrates on capturing humanoids to
turn them into thralls and illithids. Operating individually
or in small groups, its members use stealth and
deception to infiltrate the humanoid community while
keeping their presence secret. Lacking the numbers or
the ability to overwhelm and dominate the entire population,
a colony turns its research toward more effective
ways to exert control, such as finding a way to amplify
an elder brain's power to enable it to exert influence over
a greater distance.
Destruction. Because mind flayers are physically
weak, they can't rely on simple combat to stand up
against their enemies. If a colony finds itself in circumstances
where it can be outwardly aggressive, its
members likely focus their research on ways to cause
mass casualties with minimal risk to themselves, such
as plagues or methods to bring about famine and other
natural disasters. A mind flayer colony using this strategy
collects and feeds on humanoids mainly to use
the knowledge they gain to understand their victims'
strengths and weaknesses, with the ultimate goal of
finding a way to dispense with all of them at once.
Subversion. As a compromise between control and
destruction, a colony might attempt to seize control of
a few key elements of a humanoid community, and then
mix in a few, calculated destructive acts to send the
humanoids into an inexorable decline. If the illithids
can engineer the collapse of a society's central authority,
such as by inciting years of famine while driving
the local nobility to bouts of madness through psionic
assaults, they can create widespread unrest that the
colony can use to its advantage. The mind flayers can
become more expansion-minded, confident that any
response from the humanoids will be too scattered to
threaten them.
Many of the esoteric research topics pursued by a colony
reflect the ambitions and priorities ofthe elder brain
that controls it. Each one has particular ideas about how
best to contribute to the ultimate success of the Grand
Design, including these possibilities:
• The discovery and destruction of all githyanki creches
• Collecting creatures and instigating insanity in them
to create new flavors of thought
• Fostering a school of wizardry to attract intelligent
minds for the colony to feed upon
• Rediscovering the secrets of nautiloid manufacture to
take to the sky
• Drawing a surface city into the Underdark

Mind flayers never truly ally with any creatures. They
either attempt to seize control of a population by subverting
its leaders, or they use psionics to dominate a
humanoid and turn it into a thrall.
Illithids sometimes infiltrate an Underdark tribe of
humanoids and use their superstitions and traditions as
tools to make them useful followers. A mind flayer might
use its psionic ability to send visions to a humanoid shaman,
causing it to proclaim the mind flayers as emissaries
of the gods. With that ruse in place, the "gods" then
dictate strict rules that cause some members of the tribe
to be branded as heretics, to provide the pretense for occasionally
seizing a humanoid and devouring its brain.
After the colony depletes and demoralizes the popula-
tion sufficiently, the illithids might move in en masse
and attempt to turn the remaining followers into thralls.
The process of transforming a creature into a thrall
requires the entire colony's energy and attention, making
it no small matter. Although it takes only one mind
flayer to perform the process, any illithid not directly
involved in the process is required to donate its psionic
power to the effort while otherwise remaining inactive.
A thrall-to-be is first rendered docile through psionic
means. Using a low-power version of its Mind Blast ability,
the mind flayer bombards the victim with energy that
washes through its synapses like acid, clearing away its
former personality and leaving it a partially empty shell.
This step takes 24 hours. Over the next 48 hours, the
illithids rebuild the victim's memories and personality,
and the victim gains the skills and talents it needs to
perform its intended function.
The process that creates a thrall changes almost
everything about the victim. The creature retains its
Hit Dice, hit points, racial traits (but not proficiencies
granted by race), and all of its ability scores except for
Intelligence. After the first stage of the process, the creature's
Intelligence is halved; when the second stage is
over, its Intelligence score increases by ld6.
To complete the process, the thrall receives a new set
of proficiencies, a new alignment, and a new personality.
Some colonies have learned how to salvage a victim's
psionic abilities during the process or how to implant
psionic powers into their thralls. Also, some colonies
know how to leave a victim's persona intact while infusing
it with a fanatical loyalty to the colony's elder brain
as well as telepathic power that allows the victim to
communicate with its new masters as if it were a mind
flayer. This sort of thrall makes a perfect spy, since most
would never suspect its true nature.
A thrall can be restored to its former self through a
combination of spells and ministration. The thrall must
have regeneration, heal, and greater restoration cast on
it once per day for three consecutive days. The victim is
restored to normal when the final round of spells is cast.
Mind flayers vastly prefer to use humanoids as thralls,
since they have a good balance of physical attributes and
proper anatomy. Animals, in contrast, require a lot of
direct oversight and lack the ability to use tools to help
maintain the colony. Among the variety of humanoids
available to the illithids, they have some preferences and

Illithids once used kuo-toa as slaves extensively, since
they proved quite easy to control. In time, though, repeated
exposure to the mind flayers' psionic intrusions
drove the kuo-toa mad. Nowadays, kuo-toa don't make
for good thralls because their insanity makes them difficult
to control. Mind flayers consider kuo-toa brains a
great treat, but they prefer to eat them raw, unsullied by
psionic alteration. Thus, they tend to eat kuo-toa soon after
capturing them, rather than attempting to keep them
penned up or docile.

Only the most desperate colonies bother using goblins,
kobolds, gnomes, and other small humanoids for
anything except food. Small humanoids do make a
good food source because they tend to gather in large
groups, and their fear and despair in the face of a mind
flayer incursion make their brains tasty to the illithid
palate. They are also relatively easy for larger, stronger
humanoid thralls to control. Small humanoids are only
rarely transformed into thralls or otherwise kept under
firm control.

Almost any humanoid creature can end up as a thrall,
and mind flayers sometimes work with whatever victims
fall into their grasp. Aside from the exceptions discussed
above, they tend to see ores, bugbears, humans,
and other similar humanoids as largely interchangeable.
Their brains all have a similar taste, and their utility as
thralls is roughly equal.

Mind flayers hardly ever use non-humanoid creatures as
thralls or develop other relationships with them. Most of
them are either too big and strong to keep penned up for
long or too limited in intellect to complete anything but
the simplest tasks. In general, non-humanoids found in
the company of mind flayers are those that the illithids
have created or bred for specific purposes. A few types
ofthese creatures warrant special mention.
Almost every mind flayer colony creates intellect devourers
and seeds the areas around its lair with a few
to keep watch, slay intruders, and lure fresh victims to
their doom.
A mindwitness represents an exception to the typical
mind flayer pattern of reproduction. If a colony succeeds
in capturing and subduing a beholder, it can use
a tadpole to convert the creature into a bizarre hybrid
known as a mindwitness. A mindwitness is a sort of
psychic hub, able to collect and amplify the illithids'
psionic power.
See chapter 3 of this book for more information on
mind witnesses.
These horrors, hated by mind flayers, sometimes come
into being when those ignorant of mind flayer lore destroy
a colony. A neothelid arises when a tadpole pool
is left untended. The tadpoles turn against each other,
and the survivor grows to immense size. Comparable to
purple worms, these behemoths devour everything in
their path.
See chapter 3 of this book for more information on

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