When in the Kingdom it is spoken of “Mind Flayers”, taverns go hushed, people curry away, some maidens faint and someone eventually calls the Secret Police. Few people ever recounter these Abominable horrors, but those that do are in immediate mortal danger. What’s less known as that Illithidea are an actual hostile alien ecology. At the apex of Illithidae lifeforms are the terrifying Mind Flayers or Illithid themselves. The most iconic and documented specimen of these are the human-sized and terrifying looking tentacle-faced shapes from many horror stories in the Kingdom, but the Illithid biome is instrincically hostile and parasitical to terrestrial life.

History (Apocryphal)

Illithidae originate from the outer galactic halo, possible from one of the lesser satelite mini-galaxies. Of their planet of origin little is knowm except that it was alleged to be a warm cthonian (icy moon with a thick undersurface ocean) moon orbiting a pulsar, where these lifeforms evolved a half billion years ago.

They originally did not have humanoid shapes, and when they learned the psionic talents of projecting their consciousness, it was with utter surprise that they discovered the unthinkable – there was apparently intelligent life in the universe besides themselves. As it happens, to Illiths the mere idea there would be intelligence other than themselves they regard as axiomaticaly,metaphysically impossible, on a deep subconscious level.

Their dead star has a divine mind of itself, and Illithids comprimize manifest sociopathic xenophobia, racism, superiority complex and utter disregard for even members of their own kind. Illithid intelligence is fundamentally alien and hostile. Collaboration between them is based on various hierarchical types of mind rape and the infliction of absolute suffering. To Illidae pain is pretty much the equivalent of a programming language.


The proverbial Illithids or Mind Flayers have a gaunt humanoid body with a squat octopus-like head. They have four tentacles around a lamprey-like mouth, and “allegedly” 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, a process which is hellish for the victims. Illithid 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, yet they are good at discerning from what direction sounds came from. Their skin is purplish blue to gray-green and covered in mucus, and is very sensitive to sunlight. They loathe sunlight, though it does not actually harm them.

Moon Beasts

Moon beasts seem to be the original progenitor species that “evolved” into latterday Illithidae.


By default Illithids are hermaphroditic creatures who in a collective spawn a extremely aggressive black goo that infects everything it touches. This material is extremely dangerous to terrestrial life. Illithid use this material to turn all life against itself, but the central aspect of this process is the creation of new members of their species. Illithid Larvae can be extremely diversified and are manifestations of Illithidae biome.

Existing Illithids “twist” these shapes into more or less recognizable versions of themselves, or infect other life with it to “reprogram” the bodies to suit their perverse whims, generally rearranging flesh in unspeakable manners. By default infection with Illithid seed will result in infection leading to something of the primordial and ancient Illithid ecology to erupt, stalk around and cause general terror and mayhem.

The “structured” Illithid tadpoles however become their ‘citizens’, for lack of a better word, and are inserted into a (preferably conscious) creature. In the Dreamlands it so happens that for several ten thousand years these creatures have been largely been humanoid in nature, so most Illithds encountered just happen to be humanoid – but this is coincidental.

Upon being implanted (through the ear canal often), the larva then grows and consumes the host’s brain, absorbing the host’s physical form entirely and becoming sapient itself, a physically mature (but mentally young) Illithid. This process is called ceremorphosis. Illithids often experiment with non-humanoid hosts, but ceremorphosis involving other creatures is not particularly popular among them. The transformation between the host (almost always a human or similar humanoid, such as an elf) takes about a week, and formal death occurs (on account of the brain being gradually devoured) in about thirty minutes of injection into the incapacitated host. 

When an Illithid undergoes ceremorphosis, it can occasionally take on some elements of the absorbed host creature’s former mind, such as mannerisms. This typically manifests as a minor personality feature, such as a nervous habit or reaction (e.g., nail-biting or tapping one’s foot), although the process that determines the type and number of traits so inherited appears to be stochastic. Some adult Illithids have even been known to hum a tune that its host knew in life. Usually, when a mind flayer inherits a trait like this, it keeps it a closely guarded secret, because, were its peers to learn of it, the Illithid in question would most likely be killed or enslaved. This is due to an Illithid legend of a being called the “Adversary”. The legend holds that, eventually, an Illithid larva that undergoes ceremorphosis will take on the host’s personality and memory in its entirety. This Adversary would, mind and soul, still be the host, but with all the inherent abilities of an Illithid. Occasionally, ceremorphosis can partially fail. Sometimes the larva does not contain enough chemicals to complete the process, 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, personality and digestive 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.

Illithid society also maintains a long-standing taboo related to deviations to or failures of the ceremorphosis process and hunt and destroy such exceptions. Occasionally mind flayer communities are attacked (often by vengeful Githyanki and Githzerai) and their 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 (brains). This unmorphed larvae is known as Neothelids. 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.

Githyanki, Githzerai (and others)

Flayers hold slaves. These slaves do not have a particular long shelf life, and get eaten in at best a few months.Smaller humanoids het eaten immediately and Illithids especially favor gnomes as a delicacy. In the past some slaves learned how “to last longer”, by being particularly good slaves. Illithidae, despite their superficial genius, are not always universally smart, and their arrogance may lead them to make long term mistakes. This happened about a thousand years ago, where a particular slave learned to organize an armed resistance against the Illithdae, and more or less destroyed half the Illithids in the local Dreamlands. It is said this person is now referred to as “The Great Adversary” and the topic of this is a source of immeasurable fear and anger on behalf of the Illithids. To them such an event was categorically unthinkable. The name of this slave was one “Gith”. It is said this slave rebellion has in fact spread to numerous world across the galaxy, even to nonhuman races, and that the Illithid are affraid of nothing – except for one – The Great Adversary.

The Great Adversay

It is rumored the Great Adversary (or “Gith”) is still alive and well in the Kingdom, and is actually a Wizard and Grandmaster Psionicist of some reknown, who is able to transform psionically into one of the monstrous Gith ecology lifeforms, a socalled “Dark Eraser”, but very few know this. It is said this individual is able to change back and forth between male and female, and referred to sarcastically as “that Mary-Sue” by the higher ranking Wizards of the Kingdom. The Githyanki and Githzerai are aware of him, but do not venerate him in any way. Instead the title of “Gith” has been subsumed by a former lover of The Great Adversary,


Byakhee hate Illithid life and have been known to effectively hunt them to the point of suicidal atacks. 15 years ago such an attack ocured in Dylath Leeen as dozens of Vyakhee suddenly swarmed ‘the Citadel of Pain’ attacking any Illithid there indiscriminately, and in a rabid frenzy. Byakhee are mostly immune to psionic attacks. 


One of their most feared powers is the dreaded Mind Blast, where the illithid emits a cone-shaped psionic shock wave 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 from lineage to lineage. Other powers include a defensive psionic shield and powers of psionic domination for controlling the minds of others.

The Prince of Dylath Leeen

It is known the Prince has some kind of leverage over the Illithid and Moon Beasts.  They dare not attack him, and he uses them for many assignments.