From 1d4chan
Time to slurp brains

Illithids (also called Mind Flayers) are cool, and by cool, I mean totally sweet. They look like tiny little, skinnier, wingless Cthulhus, wear black robes with high collars and eat brains. Plus they all have psionic powers and are so super-smart even their breakfast is JUST AS PLANNED! They would be totally Mary Sue, except for the fact that they are so brain-damagingly evil it makes them awesome instead of lame. (There was one good one in the Book of Exalted Deeds, but nobody gives a crap about her, so let's move on.) Their psionic version is much better than their Monster Manual version by virtue of increased versatility. According to the book Lords of Madness they came from THE FUTURE.

The Illithid is considered "Product Identity" by Wizards of the Coast and as such is not released under its Open Gaming License. However, "half-Cthulhu creeps" and "squidface brainsuckers" are totally okay, so go nuts.

The illithid first appeared in the official newsletter of TSR, The Strategic Review #1. They then appeared in the Eldritch Wizardry supplement for Original Dungeons & Dragons. Since then, they have have appeared the first Monster Manual of every edition. In second edition they got a whole book to themselves called The Illithiad, and in 3.5 they got a chapter in Lords of Madness.

Fiend Folio in describing the githyanki (and githzerai) retconned that the 'flayers have enslaved humans - or will enslave them - and that they escaped/will-escape into a scourge perhaps even worse than they are/were/will-be. (Grammar gets kind of fuzzy with time diddlers.)

Dragonlance in a rare diversion into sword-n'-sorcery mooted a subrace of "degenerate" illithids, the Yaggol. These have retreated into Taladas' jungle, losing all of their psionic powers except for Mind Blast. On the upside, they are much stronger, stand 7 feet tall, and have chameleon-like skin.

Fun fact: in the city of Stormreach, in the Eberron campaign setting, there is an Illithid who just hangs around near a garden and engages in perfectly normal, honest, and voluntary business transactions with the humanoids and other races that inhabit the city. And by "normal" we mean people pay him to reprogram their brains and alter their memories. Why spend four years studying a new language when you can learn it by spending four minutes letting Fred gnaw on your brain? Oh, yeah, his name is Fred. It's a very common Mind Flayer name. Point is, Mind Flayers don't just compulsively kill/consume humanoids on sight like the xenomorphs from the Alien movies; they're perfectly capable of being normal, well-integrated members of surface-dwelling, non-evil, humanoid societies.

Illithid Physiology[edit]

Illithids consist of... purple, mostly. Just brains and purple.

Their alien physiology has stumped our crack (addict) biology team even after years of scientific scrutiny. It is thought that if we could crack the mystery of why these skinny creatures subsist on a diet of nothing but fat and calcium, we would be closer to... something.

Look, just look up "aberrant" in the dictionary. We can't offer you much for the time being.

In actuality, Illithid physiology is a moderately altered version of their host organism's body (see mating practices). The brain of the host is replaced by a tadpole thing, and the digestive tract is altered to aid in the consumption of brains and their psychic essence. And of course, they grow tentacles and Sarlaac mouths and lose all of their hair.

Explained somewhat in 3.5's Tome of Darkness, the resulting creature is entirely conscious of its organs and body, as opposed to being autonomous. There is a tiny part of the creature's powerful mind constantly remembering to make sure the heart beats, and regulating digestion. Things like that. So they eat normally, and extract maximum nutrition from it. The method of creating an illithid destroys the brain, which includes all those hormone producing glands in the skull that keep a person healthy. This is why they need brains to keep their body from decaying. The memories and thoughts consumed are... well "flavor" to put it in the least disgusting way possible. These memories, thoughts, and emotions are just as necessary as the hormones contained within the brain for an illithid that consumes only the brains of unintelligent creatures or animals will regress into a ravenous beast, actually pretty similarly to the Kroot.

There is apparently a cult of illithid monks/clerics known as The THOON (yes all caps) who worship a god or philosophy also known as THOON (see below for more on THOON and The THOON). They minmax their bodies as well as their minds. The elder brains hate them. They've been out of circulation since 4e landed. But if you need a mastermind who can roundhouse kick the fighter through a wall after the party blitzes through his mooks, look no further.

For the morbidly curious about what'd happen if you ate an illithid's brain, according to 5e's Volo's Guide to Monsters, nothing good. Apparently, each bite into an illithid's brain releases an intense flood of memories that the illithid developed/consumed in its life, so strong it'll probably drive the typical consumer insane. As to how Elminster knows this, he refuses to explain.

Illithid Mating Practices[edit]

This drow is in for a Bad Time.

This morbid fascination of yours is going to get you killed one of these days, you know that?

Anyway, if you've ever seen that Bruce Campbell movie Mindwarp, with those burrowing leech things, you've got a pretty good grasp on what to expect. Consider this your warning.

Twice in an illithid's life, it will go to the pool containing the mind flayer community's Elder Brain (though any briny pool will do), and literally vomit a huge amount of tadpoles out of their mouth (they're asexual like that.) These tadpoles will be nurtured (though the elder brain will eat some of the tadpoles, who themselves engage in cannibalism) over the course of ten years (20 for ulitharids) and once they are ready, they are taken from their pool to undergo Ceremorphosis.

An unlucky creature will be restrained as the tadpole is brought to it, and the mind flayer carrying the tadpole will place it within the most direct route to the brain (typically the ear or nose, which makes no sense since neither of those connects to the brain, but the eye socket does so it could still work) and the tadpole will quickly burrow its way through the skull and into the brain where it will devour the host organism's brain over the course of a week as it alters the host with mind flayer traits. Not all tadpoles are able to integrate into the host body to the same degree, such that sometimes the resulting illithid is left with the impression of piloting its body rather than of being it. Very, very rarely the transformation process itself partially fails and no external changes are brought about (though it will still internally be a mind flayer and need to eat brains) in these cases the new mind flayer is used as an infiltrator for obvious reasons. Even rarer, to the point where it's practically considered an urban legend is the opposite, where the host undergoes the full transformation, but their original mind remains intact and in control of their newfound powers. Mind flayers are scared shitless of these creatures, referred to collectively as The Adversary. Not only are they perfectly capable of blending in flawlessly with mind flayer society, they are almost certainly in the vengeance-seeking mindset, and in the perfect position to bring it all crashing down on their tormentor's heads.

When the process is complete, no form of magic or psionics, excluding wish and reincarnate and true resurrection, can bring back the victim, but even then the mind flayer will still be alive. Aside from that, nothing can reverse the effects; there is no way to bring back the original host, so he/she/they is for all intents and purposes, dead forever. Though the newborn mind flayer will be physically mature, it will take some time to mentally mature (though its community will be more than willing to assist it in this manner).

If the host is any species besides a human, the result is a half-mindflayer, whose template can be found in the Fiend Folio. Special cases are present though; placing a mind flayer tadpole into a beholder results in a mindwitness (essentially replace four of the eyestalks with large thick tentacles and the rays of doom with psionics), a docile creature whose main role is to facilitate telepathic communications. A Mind Witness will look for another telepathic being to serve if the illithids it works for die. Placing it within a true dragon results in the unspeakably powerful gribbly horror that is the Brainstealer Dragon, whose psychic might is only surpassed by the Elder Brain. Put it in a Roper and you get the urophion, a creature with a genius level intellect whose talents are wasted on sentry duty due to racism (but with their slow, slow, slow move speed they can't do much of anything else). Implanting one in a Svirfneblin usually kills both the tadpole and its host, but if it survives the result is a mozgriken, a small shapechanging creature with no mouth and only three tentacles, a trait that forces them to feed only on brain fluids and earns them no small amount of abuse from true illithids. The tadpoles typically placed within lizardfolk are more bellicose than their kin, and form the Tzakand- creatures similar to lizardfolk save for the two acid-spitting tentacles emerging from their heads that become fanatically loyal to the first illithid they see. If a tadpole is placed into a Chuul, the tadpole dies, but the Chuul is changed into a creature called an uchuulon, or a slime chuul, which is like a chuul, but slimier.

If a tadpole is not placed into a host and is placed in the wild (which normally happens only in spawning pools whose Elder Brain is dead, as it eats all tadpoles that do not undergo ceremorphosis), it will eventually eat and grow into a gigantic fucking psychic worm of doom called the neothelid (think the dune sand worm, only quite a bit smaller and with tentacles and head asploding psychic powers) with only minimal sentience- that is, unless it eats a sentient creature. Regular Mind Flayers consider it highly taboo to speak about neothelids (probably because neothelids remind the illithids too much of their "natural" state which their progeny would devolve into, were it not for the availability of suitable hosts their tadpoles could Ceremorph), and to actually create one is outright forbidden. Oddly, neothelids are not considered Product Identity by Wizards of the Coast, possibly because "giant slimy worm that spits acid and shoots mind bullets" would not have been copyrightable. No word on whether neolithids ever develop the capacity to birth tadpoles of their own.

One out of a hundred or so tadpoles will take twice as long to become ready for ceremorphosis. These tadpoles will create ulitharids when implanted into a host. Ulitharids are large sized and have two extra long tentacles and much more powerful psionic abilities. They also live for a lot longer than normal mind flayers. Sadly, the only statistics for ulitharids are for ulitharid tadpole/human combinations, which is a disappointment since an ulitharid brainstealer dragon would have been fuck-awesome. Fifth edition updates their lore such that if elder brains can be compared to queen bees, then ulitharids are analogous to juvenile queen bees. After serving as a colony's majordomo for a while, ulitharids eventually get sick of having to live in the elder brain's house and therefore live by their rules, so they move out and start their own colony (with blackjack and hookers). Soon after they find a good spot, the ulitharid uses their fancy staff to basically crack their own skull open like an egg and have their brain put in a special pool, where it soon develops into a fully fledged elder brain.

Elder brains are created via a process that varies from edition to edition (in those editions that elaborate on the process at all, that is). In some editions all ulitharids that survive long enough eventually morph into one. In others it happens when a bunch of deceased mind flayer brains are dumped into a single pool filled with a briny solution; these brains will merge and eventually become alive and turn into a CR 25 TPKing horror. There is also an idea that elder brains were created by the Illithid god Ilsensine, who performed ceremorphosis on some lesser gods or demigods. One of them, called the "Illithid God-Brain," is even trapped on Ravenloft and rules over an Illithid colony named Bluetspur, with the official backstory left open as to why one of these alien monstrousities would ever earn the place of a Darklord on that benighted plane, save that it must have done something atrocious even by Illithid standards. And with Van Richten's Guide to Ravenloft, we finally have the answer: this elder brain started cannibalizing other elder brains to help it discover a concept that was utterly alien, even to it! But it developed a degenerative disease as a result of the cannibalism, which scared the other elder brains into attempting to banish it from reality in fear of the disease spreading.

A rare few Illithids who end up mastering actual arcane magic instead of psionics opt to become Liches, named Alhoons or Illithiliches, since Elder Brains can't absorb magical abilities from the brain of an Illithid mage and magical talent (unless it's that of a Cleric to Ilsenine, see below) is looked down on in Illithid society. These squid-faced liches are extremely dangerous examples of psionic undead and can still rip your brain from your skull despite having no need to consume brains after the transition to undeath, with no explanation being given for how they still continue to secrete the biocorrosive slime needed to soften the flesh and bone of the skull to allow for easy extraction of living brains while undead (and thus having no metabolism to speak of).

Even more rare than Alhoons are Illithid vampires, who are created by unknown means. Unlike Alhoons, Ilithid vampires still need to consume brains to survive, plus retain the thirst for blood that vampires are cursed with. The process that turns them into vampires also affects their brains, as the majority of their intellect is replaced with feral instincts and a savage cunning streak. Fifth edition gives us more on their lore by having them be the servants of the Elder Brain overlord of Bluetspur, created by infecting Illithid tadpoles with vampirism before implantation. These creatures then go out into the world to complete their only mission: draining cerebral fluid from sapient creatures. Once this objective is fulfilled, they return to the Elder Brain's pool, where they are then dissolved into the brine, releasing the cerebral fluid which is used to stave off the dark lord's degeneration. Despite this, vampiric mind flayers are (rightly) considered by their living brethren to be abominations.

The fifth edition adventure Icewind Dale: Rime of the Frostmaiden introduced two more Illithid variants. A gnome ceremorph is an illithid created from a gnome host that failed to completely change into an illithid and so retains some of the physical and mental traits of a gnome, making them shorter than a regular illithid, but talented at invention. They wield laser pistols and are the same alignment as before their transformation. A gnome squidling is an pathetic and kind of adorable variant of the gnome ceremorph that came out horrifically wrong with a stunted body, an oversized head, big eyes, and a pair of tentacles that are way too long. They have to use levitation to move around and their mind blast attack is replaced with a much weaker mind tickle attack. Their lack of intelligence makes them unaligned.

Illithid Society[edit]

An elder brain in his pimped-out floating vat

Illithids function as a hive mind, serving the Elder Brain. Other than maintaining the Elder Brain, the day-to-day duties of the average illithid consist of evil science and making cheeky wood burnings. The purpose of these wood burnings is an inextricable mystery, as they seem to disappear shortly after their completion. They can make Brain Golems out of buds from said queen-like Elder Brain, which are exactly what they sound like and exactly as retarded as you would think. Even the Illithids and the Elder Brain itself know how impractical this can be, and would prefer to use any other type of golem instead. The Illithids live for the fact that after they die, their brains, and thus their minds, will be merged with the Elder Brain after death. This is, of course, complete and utter bullshit, as the Elder Brain just eats their knowledge and discards everything else (although pretty much nobody in-universe aside from the elder brains themselves is aware of this). Elder Brains discourage studying magic too much because Elder Brains can't eat a mind flayer's magical abilities, though they can eat a mind flayer's knowledge of psionics (if it ever took levels in Psion, Erudite, Wilder, or what have you.) Below the Elder Brain on the mind flayer hierarchy are the Brainstealer Dragons (very rare because it's notoriously difficult to restrain a true dragon) and the Ulitharids.

The mind flayers have one deity they pay respects to in Illsensine, who did not create them. Perhaps to make up for the fact that Illsensine is the only Mind Flayer God, Illsensine is a very powerful rank 20 greater deity who omnoms the knowledge of everyone the instant they die. The Mind Flayers don't exactly worship Illsensine per se, they just respect it for its great knowledge, and Illsensine returns the favor by considering Mind Flayers to be the only worthy species in the multiverse. This is not to say that there are no Mind Flayer clerics to Illsensine, because said clerics of Illsensine do indeed exist, but their numbers are rather small relative to say the number of Dwarven clerics of Moradin, however; Mind Flayer communities have an exception to their rule of "don't study magic too much" for the Clerics of Illsensine, and in fact greatly respect these clerics and leave them to their business.

The mind flayers used to have another god called Maanzecorian, but Tenebrous (actually Orcus, it's a long story) used the last word on him, so his head asploded.

Some illithids spend their time finding ways to put out the sun, because they hate that bright light shit. Unfortunately for them, putting out a 1,392,000+ kilometer ball of ungodly hot hydrogen and helium is nigh on impossible (unless your name is Father Llymic.) Most other Illithids think that these illithids are wasting their time when it's common knowledge that all they have to do is wait many, many billions of years for the sun to eventually puff up and die. And it goes without saying putting out the sun would indirectly eliminate their food source as well.


Illithid communities are governed by a group of representatives called an Elder Concord, while the Elder Brain acts like the president. These representatives come from the various creeds or factions of illithid culture. Each creed has different beliefs about the best path towards taking over the universe. The symbols of each creeds are squares containing six horizontal bars that are either solid or split in two.

  • The Creatives devote themselves to advancing illithid society though scientific and psionic research and invention.
  • The Awaiters believe in long term planning and avoid making rash decisions.
  • The Possessors think hording wealth and resources through trade with other races is the best path to power.
  • The Tamers work to build up the illithid's military strength so they can dominate the universe through force.
  • The Thorough Biters have a philosophy of learning through failure, making them more humble that most other illithids.
  • The Nourishers promote the interest of maintaining the community's supply of thralls.
  • The Abysmal feel that the best way to dominate other races is through the power of terror.
  • The Influencers specialize in collecting intelligence and misleading their enemies through infiltration and spying.
  • The Darkeners, the dudes who think they can find a way to extinguish suns.
  • The Gatherers want to consolidate the illithid race into larger, more powerful communities instead of many small disparate ones.
  • The Arisers say that illithids shouldn't stay in darkness and so they develop ways for them to work in daylight and make plans for conquering the surface.
  • The Venerators are the worshipers of the illithid god Ilsensine.
  • The Loretakers are a minor creed, but they are important as the source of the Thoon:

Some Loretaker mind flayers (possibly) went to the Far Realm and apparently encountered something called Thoon. However, the exact nature of Thoon is unknown even to the mind flayers themselves, so whether Thoon is a god, an aberration, a philosophy, or something else entirely is open to interpretation. In any case, the encounter with Thoon changed these particular illithids completely, they're a lot more irrational and unpredictable (NE instead of LE), make use of a lot of really weird constructs and altered humanoids (and employ a variant of the mind flayer that trades the ability to control minds for ninja powers), and for some fucking insane reason a CR 25 Elder brain came back as a CR 15 entity that's totally batshit insane. Oh, and they also seek to gather quintessence for some reason.

3.5e stats[edit]

Is this copyrighted? Who cares? It's not like anyone reads this site anyway.

— +2 Strength, +4 Dexterity, +2 Constitution, +8 Intelligence, +6 Wisdom, +6 Charisma.
— A mind flayer’s base land speed is 30 feet.
— Darkvision out to 60 feet.
— Racial Hit Dice: A mind flayer begins with eight levels of aberration, which provide 8d8 Hit Dice, a base attack bonus of +6, and base saving throw bonuses of Fort +2, Ref +2, and Will +6.
— Racial Skills: A mind flayer’s aberration levels give it skill points equal to 11 × (2 + Int modifier). Its class skills are Bluff, Concentration, Hide, Intimidate, Knowledge (any), Listen, Move Silently, and Spot.
— Racial Feats: A mind flayer’s aberration levels give it three feats.
— +3 natural armor bonus.
— Natural Weapons: 4 tentacles (1d4).
— Special Attacks: Mind blast, psionics, improved grab, extract.
— Special Qualities: Spell resistance equal to 25 +class levels, telepathy 100 ft.
— Automatic Languages: Common, Undercommon. Bonus Languages: Abyssal, Aquan, Draconic, Dwarven, Elven, Gnome, Infernal, Terran.
— Favored Class: Wizard.
— Level adjustment +7.


With assets like those, who cares if she has an octopus for a head?
LamiaMonstergirl.pngThis article or section is about Monstergirls (or a monster that is frequently depicted as a Monstergirl), something that /tg/ widely considers to be the purest form of awesome. Expect PROMOTIONS! and /d/elight in equal measure, often with drawfaggotry or writefaggotry to match.

Now, you'd see the face on these things and the how of their reproduction and figure that this has to be one species that can't get the monstergirls treatment? ...But then you realize that they have tentacles, and you suddenly remember that Japan exists. "Feminized" illithids, which are basically mind-flayers with boobs and often skimpily clad, occasionally pop up in monstergirl-related threads on /tg/, usually under the same joking context as the thri-kreen/xixchil.

More importantly than that, Mindflayers are one of the "Aberrant" monstergirls that show up in the Monster Girl Encyclopedia. Formally considered a relative of the scylla, they take the form of tall, curvy, slime-dripping women with tentacles for hair and a Morticia Addams-like dress implied to actually be tentacle-legs. It also (good taste) has an ultra-high collar. They are ultra-perverted hedonists, using their psionics to brainwash victims into playmates of their obscene lusts, and are reputated to eventually transform men they take as their lovers mentally and physically into grotesque, squid-like tentacle-beasts, which spend the rest of their lives fastened to the mindflayer's hips and shoving her genitals full of tentacle-penises.

Later sources clarified that the man in question can freely transform back and forth between squid-form and human form, but that the mindflayers are uncharacteristically shy about public displays of affection when their lovers aren't tentacled, so this is only done in private. And they usually use their mind-powers to help friends engage in emotionally-resonant roleplay when in societies with other monsters.

See Also[edit]



Illithid vampire


Elder brain

Ceremorph tadpoles


Ceremorphed thralls