A Treatise on Illithids

Illithids find Heroda Fascinating. Like a playground suddenly appearing in the forest they call home, wanderers of the Far Realm have stumbled across the world very early in its creation as they cruised the far realms in their nautilus ships. They came upon a world in the throes of creation, a shard of reality shining like a beacon in the misty otherness of the far realms.
At various places of the world, Illithids made landfall after treacherous translations through the tumultuous budding spheres. Some explored and extracted resources, leaving huge scars upon the land that can still be seen to this day in some places. Others formed colonies, towers of living architectures with pulsating flesh providing transport for the unfortunately terrestrial of their thralls.
Illithid society as a whole is not the monolith. While one of the largest and most aggressive factions are that of the militant xenophobes who aim only to rebuild their dark empire from the end of time. Other factions include those that rebelled, those who pursued other avenues towards advancing their species and many who merely thought that rebuilding the empire that ultimately ran out of time would be a foolish repetition. without merit. Loosely assigned, these factions would be the Imperialist, Repentant, Accelerationist and New Path factions. Not every colony or Illithid aligns to these specific factions but most of a colonies ideologies can be loosely placed into these.
In the early eras of the world, the world was bare. Without sustenance the Illithids were forced to bring slaves from other worlds. This ultimately made Heroda an undesirable port of call for all but the undesirable of Illithid society. There were only two major Imperialist settlements on Heroda, a sprawling breeding farm known as Tanj'kere on the wide steppes of the north-eastern portion of the primordial continent that aimed to breed various humanoids for sustenance and as ideal hosts for new Illithids. A soaring city of spires perched high in the mountains near the center of the continent called Ulr-wajk-tlk served as the primary port for the world. Various other colonies cropped up in other parts of the world but without a steady supply of slaves, many of them were merely temporary settlements. Only those who did not prey on humanoids at all were able to survive if not thrive so disconnected from the rest of Illithid society, though the degradation of the elder brain in that state left the colonies who did so weaker than normal.
As the Mythic Era dawned and the beings who would become Gods and Powers started to stir, they rarely came across the relatively tiny dots of Illithid society on the planet. Instead the Illithids carried on, observing the rise of these beings with fascination and caution. The rise of sentient life in the wake of these first powers would create a more tenable position for new colonies but that very same life was protected by active divinities at the very peak of their strength. Clashes became more common though the two largest Illithid colonies kept mainly to themselves, it was not in the Imperialist factions best interests to ruin a perfectly good safe haven by clashing with gods. Few extant colonies survived the rise of the Humans, Elves and Dwarves as they spread from their creators shadow and across the lands. Those that did, burrowed deep into the ground and into the Underdark or into the spheres to hide. Some instead went back into the void, creating large platforms that orbited nearly out of site of Heroda to live on. These platforms lurked just at the edge of the planets Reality Shadow, making them almost impossible to detect from any seekers on the world but also keeping them relatively safe from the amorphous beings that lurked in the Far Realm just outside.
Throughout this rise of the mortal races on Heroda, Ulr-wajk-tlk and Tanj'kere sat safely in relative isolation, having scattered run ins with Giants and Dragons but maintaining a distant non-aggression with the worlds inhabitants. This changed with the Shattering War. The opening battle of the war cracked the primordial continent into three, breaking the high towers of Ulr-wajk-tlk and sending their vaunted Spelljammer dockyards crashing to the mountains below. Tanj'kere weathered the shattering well enough but it was a sign to the leaders of these colonies that their time on this planet was coming to an end.
Ulr-wajk-tlk was never able to rebuild its dockyards. Battles between Dragons and Giants swept over the broken city several times, causing massive collateral damage with either side only being forced out at high cost to the Illlithids. With their docks in the state they were, the Illithids were unable to land their largest ships and had to rely on smaller ones to ferry those deemed "Important" out of the settlement. The original shattering had destroyed several of their dreadnaughts and sent dozens of other ships soaring into the air untethered and drifting. Many of these ships still drift high above the world to this day and the Flying City of Kel is a human city that was built upon the overgrown remnants of one such ship.
Without much recourse, the Illithids of Ulr-wajk-tlk who were not able to escape instead dug deeper into the earth. They abandoned the ruined city above midway through the war, leaving it as a strategic prize to be fought over again and again by the Giants and the Dragons before partially reclaiming them after the final blow was struck that ended the war. Though unable to rebuild the docks, they were able to become the capital of a sprawling Illithid kingdom called Ulr by its neighbors. This kingdom would ultimately fall in the aftermath of the Rift Wars with the Dwarves and Elves of Greyharbor, dropping most of the Illithid Kingdom into the Underdark and leaving the few remaining to either be conquered or to slowly degrade.
Ulr-wajk-tlk stands in cyclopean ruins today on the southern side of the Howling Fjords, inhabited by various monsters and so far removed from the world that it is only a few dragons who know of its existence and who avoid it due to the harsh memory of the blood shed over the city in the Shattering War.
Over the next several centuries, Tanj'kere was abandoned. With much of the heavy transport capabilities lost, what thralls they could manage to fit were packed into the ships available and they left, leaving the others to the wilds and forming the core of the reclusive Tanj culture on the continent of Yrevelan that exists to this day.
Illithids in present day are rarely found on the surface and the world is very rarely visited directly by outside Illithids. Any visitors are far more likely to stop at the orbiting cities to trade for news and goods as these platforms tend to have connections to major Illithid colonies on Heroda. In this new world however, other factions of Illithids would rise to become the primary ones found, creating an interesting cultural exchange between colonies and making for an utterly unique situation that Illithids from outside can find as disgusting as they do compelling.