Illithid Empire

The Illithid EmpireThe article refers to the multiverse-spanning empire of the Illithids, not Nihilath, a singular illithid empire found somewhere in the Underdark. was the multiversal empire that spanned many planes of existence, long before the history of the multiverse was recorded.
==Organization==
At its height, the illithid race held control over vast swathes of the astral and ethereal planes, countless planets on the Prime Material plane, and even the furthest edges of the Outer Planes.
==Activities==
To continue their ongoing conquest, illithids harnessed the power of the stars themselves. They partitioned entire planes of existence to house the peoples they enslaved, who served as mere pack animals or fodder for their expansive war. One such race that was subjugated by the illithids was the gith. It was these people who would come to bring about the end of the great illithid empire.
As they conquered world after world, the imperial illithids exterminated an untold number of humanoid races.
==Tactics==
To travel from world to world, the illithids employed unique magic to create spelljamming vessels, known as nautiloids.
==Base of Operations==
The great Illithid Empire originated from the artificially-created world of Penumbra. The colossal, artificial world was larger than the orbit of many planets, created out of substare in the shape of a perfectly flat disc. Within the center of Penumbra was a singular gaping hole, within which rested a star. 
==History==
It was believed that the illithid race was so ancient, that it predated all of recorded history. According to one myth they originated on a world that was shrouded in "eternal night", that was destroyed in some calamitous event. The illithid were said to have overthrown the repression of their own creator race, then fled their doomed planet in space-faring vessels.
The Illithid Empire rose up before the existence of many peoples across the multiverse, and their power soon became all but absolute. The threat of the empire against all existence was so profound, that even the archdevils of the Nine Hells at one point temporarily ceased their campaigns in the Blood War in order to act upon the emerging threat.
===War of Rebellion===
The Illithid Empire faced several slave revolts throughout its existence, and nearly all were put down by the mind flayer's―as they were more commonly known―potent psionic powers. Over time, illithid slaves began to develop minor resistances to psionics, and those clever enough to hide the protection they possessed even came to develop their own latent abilities of the mind. 
A single leader named Gith rallied forth her people―a group that would come to bear her name―approximately 2000 years before the Faerûnian Era of Upheaval, and together they overthrew their inter-planar oppressors. Other heroes rose to prominence in the great rebellion, such as Vlaakith I, who urged Gith to unite allies from across the planes and bargain with the goddess Tiamat, and Gith's own son Orpheus, the fallen Prince of the Comet. The individual known as Zerthimon became a prophet to his own people, and spread the knowledge of how to effectively combat the illithids to others.
Penumbra itself even fell to the thralls of the illithids. The myriad slave races overthrew their oppressors and threw the world itself into chaos.
====Alternate Theory of the War's Origins====
There remained one outstanding and contradictory theory about the Illithid Empire, at least which was overthrown by the great gith rebellion. It was believed by some that it was not founded by illithids that overthrew their progenitors, but had arrived from some unknowable future. The entire illithid race faced extinction in the farthest reaches of future―the literal end of time. The most ancient elder brains sacrificed themselves to create a colossal psionic storm that allowed some of their kind to be hurled backwards in time. This accounting of the Illithid Empire was recorded in the Sargonne Prophecies.
Ironically, it was speculated that the progenitors of the gith race were brought to the time preceding the great rebellion, by those illithids from the future that were fleeing their inevitable doom.
===Downfall & Aftermath===
Regardless of the illithids' origins, Gith and her people earned their initial victory in earnest. Word of their victory spread, and world after world that remained under illithid control liberated themselves from their imperial overlords. A dwarf by the name of Laduguer of clan duergar struck a deal with Archdevil Asmodeus for the power needed to overthrow the illithid's on his home world. The illithid race was slaughtered en masse across the cosmos. 
While their once-mighty empire was toppled, few surviving illithids remained after the great rebellion. Their race was forced to live in small, isolated communities, led by singular elder brains that were forced to enslave small scores of lesser beings to merely survive. Some managed to hide themselves away in deep, underground fortresses where few interlopers dared to tread. One crew aboard an illithid planetismal managed to cross through several crystal spheres before landed in a massive crater upon some unknown world.
Remaining illithids were hunted down like animals by the githyanki rrakkmas, one of the two divergent races of the original gith people.
===Return===
The illithid remained as they ever were, an exceptionally patient and calculating race. Over the course of the following millenia, isolated elder brains formulated plots to return to existence the once-great Illithid Empire. This philosophy among the illithid people was known as the Grand Design. Unfortunately for the remaining elder brains, the knowledge of how their first empire arose―along with the specifications to build new nautiloids―had been lost to the ages. 
Individual efforts to carry out the Grand Design were repeatedly ended, often by the ever-vigilant githyanki who swore vengeance upon their long-ago oppressors. It was theorized by some however, that even the subterranean illithids of the impossible future―who dwelled on cold, husk planets nourished only by near-spent stars―would form their empire once again. It was said they would consume all hope from existence in their unimaginable cruelty. 
====On the Overmind====
In the city of Stormport on some unknown world, an ulitharid called Shuluth schemed to darken the star around which the planet rotated. It would assimilate the surface population in preparation for the coming of the "True Masters".
The True Masters appeared to reference an Elder Concord―a conclave of illithids from across the multiverse―that gathered shortly thereafter to discuss the discovery of gaps in the ethereal plane. The concord manage to construct a circular ring around one of these 'ether gaps', a device known as the "Overmind". The illithids hoped to utilize complex psionic machinery―known as the Engine Consummate―within the Overmind to siphon energy from hundreds of stars, to turn the adjoining ether gap inside-out, and replace their current reality with one in which their empire still reigned supreme.
====On Toril====
One elder brain on the planet of Toril came ever-closer to achieving the Grand Design by manipulating three servants of local deities to do its bidding. It utilized a specialized form of latent ceremorphosis, which remained undetectable to traditional means, to infect many in the late 15 century of the regional calendar. If successful, the infected would transform into mind flayers at the elder brain's command, and rapidly overwhelm the entire continent.
A rogue illithid known only as the Emperor captured several individuals aboard a unique nautiloid, and infected with the same mind flayer tadpoles that inflicted latent ceremorphosis. He however also protected them with a mysterious artifact of gith origin, that prevented them from falling under the control of the elder brain and its three servants.
==Legacy==
The rise and fall of the Illithid Empire had consequences that spanned the breadth of the universe, some of which would not likely have been expected. It was the technology found within illithid nautiloids for example, that inspired the invention of githyanki astral ships and other vessels capable of navigating wildspace.
==Appendix==
===Notes===
===Appearances===
===References===