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Mind Flayer

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The Illithid

In the planets of Toril and Eberron, illithids (commonly known as mind flayers due to their considerable psionic powers and appetite for brain matter) are monstrous humanoid aberrations with Psionic powers. In the Forgotten Realms, they live in the moist caverns and cities of the enormous Underdark. In Eberron, the illithid come from Xoriat, the plane of Madness. They were created by the Daelkyr in their invasion plans. It is not known if they have elder brains, but their continued existence implies that they can breed on their own. The mind flayers of Eberron are resistant to damage from all weapons except those made out of byeshk, a new exotic material on the planet. Illithids believe themselves to be the dominant species of the multiverse and use other intelligent creatures as Thralls, Slaves, and Chattel. They are evil and sadistic beings, and unparalleled in their mastery of psionic powers. Utgar has summoned Mind Flayer Masterminds to serve in his army.

Typical physical characteristicsEdit

Illithids have a basic humanoid body, but their head is Octopus-like. They have four tentacles around a Lamprey-like mouth, and require the brains of sentient creatures as part of their diet. An illithid who snares a living creature in all four of its tentacles can extract and devour its living brain. Their eyes are pale white, and they can see perfectly well in both darkness and light. Their sense of hearing is slightly poorer than a human's; they have difficulty distinguishing between several sounds mixed together. Their skin is purplish blue to gray-green and covered in mucus, and is very sensitive to sunlight. Though sunlight does not actually harm them, they loathe it with incredible ferocity.

One of the most feared powers is the dreaded Mind Blast, where the illithid emits a cone-shaped Psionics shockwave with its mind in order to incapacitate any creature for a short amount of time. Illithids also have other psionic powers, generally telepathic in nature, although their exact effects have varied over editions. Other powers include a defensive psionic shield and powers of psionic domination for controlling the minds of others.

Illithid biologyEdit

Illithids are Hermaphroditic creatures who each spawn a mass of Larva twice in their life. The larvae resemble miniature illithid heads or four-tentacled tadpoles. Larvae are left to develop in the pool of the Elder Brain. The ones that survive after 10 years are inserted into the Brain of a sapient creature. Hosts are determined in a very specific manner. Hosts generally are Humanoid creatures that are between 5 feet 4 inches and 6 feet 2 inches. The most desirable of races for hosts are Human, Drow, Elf, Githzerai, Githyanki, Grimlock, Gnoll, Goblinoid, and Orc. Upon being implanted, the larva then grows and consumes the host's brain, absorbing the host's physical form entirely and becoming sapient itself, a mature (but still young) Illithid. This process is called ceremorphosis. Illithids often experiment with non-humanoid hosts, but ceremorphosis involving other creatures usually fails, killing both host and larva. Occasionally, ceremorphosis can partially fail. Sometimes the larva does not contain enough chemicals to complete the mutation, sometimes there is psionic interference. Whatever the reason, it has happened that ceremorphosis has ended after the internal restructuring, resulting in a human body with an illithid's Brain and Gastrointestinal tract. These unfortunates must still consume brains, typically by cutting open heads (as they lack the requisite tentacles). These beings are often used as spies, where they easily blend in with their respective host types.

The illithid Society also maintains a long-standing Taboo related to deviations to or failures of the ceremorphosis process and hunt and destroy such exceptions. Every so often, a mind flayer community is attacked (often by vengeful githyanki and githzerai) and its inhabitants must flee. This leaves the larvae unattended. Bereft of exterior nourishment, they begin to consume one another. The survivor will eventually leave the pool in search of Food (i.e., brains). This unmorphed larvae is known as a Neothelid. If the neothelid consumes an intelligent creature it will awaken to sapience and psionic abilities and grow to immense size, while retaining its memories of savage survival. In Complete Psionic, it was revealed that illithids have a step between larva and neothelid called a Larval Flayer, which looks like an overgrown Tadpole. The existence of these beasts is a guarded secret among illithids, and it is considered impolite to speak of them.


Currently, the illithids are in a period of intense study and experimentation, gathering knowledge of all sorts that will enable them to eventually reconquer the universe and hold it for good. They frequently meddle in the politics of other races through subtle psychic manipulation of key figures, not to cause chaos but so as to better understand the dynamics of civilization. They regularly probe the minds of surface dwellers so as to gather intelligence and learn about new advances in magic and technology. They also do a good deal of research themselves, mainly focused on developing new psychic powers.

Illithids regularly conduct raids on all sentient settlements to acquire new thralls, because their existing stock of sentient thralls do not breed fast enough to satisfy their food and labor needs. Typically, a group of mind flayers will teleport to the settlement and swiftly incapacitate them with their psychic powers. The captives will then be marched all the way to the illithids' underground settlement by specially trained and conditioned thralls. Great care is taken to cover their tracks.

Mind flayer
A Mind Flayer Mastermind


An illithid city is ruled by a creature called an Elder Brain which lives in a pool of cerebral fluid in the city's center. When an illithid dies its brain is extracted and taken to the pool. Illithids believe that when they die their personality is incorporated into the Elder Brain, but this is not the case. When the brain of an illithid is added to the Elder Brain, the memories, thoughts and experiences are consumed and added to the sum of the whole, but all else is lost. This fact is a closely guarded secret of the Elder Brains, since all illithid aspire to a form of immortality through this merging process. An extremely ancient Elder Brain is called a God-Brain because its psionic powers are almost limitless.

Since the Elder Brain contains the essence of every illithid that died in its community, it functions in part as a vast library of knowledge that a mind flayer can call upon with a simple telepathic call. The Elder Brain in turn can communicate telepathically with anyone in its community, issuing orders and ensuring everyone conforms.

Illithids generally frown upon magic, preferring their natural psionic ability. Psionic potential is an integral part of the illithid identity, and the Elder Brain cannot absorb the magical powers of an illithid mage when it dies. They tolerate a limited study of wizardry, if only to better understand the powers employed by their enemies. However, an illithid who goes too far and neglects his psionic development in favor of wizardry risks becoming an outcast. Denied the possibility of ever merging with the Elder Brain, such outcasts often seek their own immortality through undeath, becoming alhoons.

Illithids typically communicate through psychic means. They project thoughts and feelings to each other in a way non-illithids can scarcely comprehend. When they do feel the need to write, they do so in "qualith." Instead of typical alphabet-based writing, illithids write in qualith by making marks consisting of four broken lines. They use each tentacle to feel the breaks in the lines, making it basically similar to braille. However, qualith is extremely complex, as each line modifies the preceding lines through explaining abstract concepts associated with the above words in ways no human can understand; only by understanding all four lines simultaneously can the meaning be understood properly.


Traditionally illithids revere a perverse deity named Ilsensine. Although Ilsensine is the illithid patron deity, few mind flayers actively worship him, thinking themselves the most powerful creatures in the universe.

Relations with other racesEdit

Illithids seek to rebuild their former empire wherein all other species were their slaves, so they view any sentient creature as worthy only of being their slaves or their food. They are pragmatic, however, and will trade with other races, such as dark elves and gray dwarves, who are too strong to be conquered. They also trade with the Neogi in order to obtain slaves.

Their archenemies are the githyanki and the githzerai, descendants of the rebellious slaves who destroyed their empire millennia ago. Hunting and slaying illithids whenever they can is an integral part of their cultures.

Illithids fear the undead because these creatures, even the sentient ones, are immune to telepathic detection and manipulation, and have no brains to consume. Confronting such mindless creatures can even be traumatizing to some of them.

According to the Lords of Madness history, Illithids are one of the only races respected by the aboleths. This is because the aboleths remember the origin of almost every other race, through their hereditary memory. However, illithids, as far the aboleths can remember, just appeared without preamble, which scares them.

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