Mindflayers

Illithids, more commonly known as Mindflayers, are a race of humanoid creatures with advanced psychic powers. Their most defining features are their bulbous, squid-like heads and their tendency to devour the brains of victims that they do not enthrall into servitude.

Rumors
Rumors of the existence of the Mindflayer city first began when beggars, vagrants and other lower-class citizens started to disappear from the streets of Qatif, only to reappear as corpses in the sewers, their skulls noticeably bored into and their brains missing.

War Beneath Qatif
With all the districts of Qatif and the Mul united, the Shards of Khaios were able to split up to lead battalions of elves, dwarves, humans and Mul into the tunnels beneath the city in a head-on assault of the Mindflayer city. Their forces were met with heavy resistance from the Mindflayers and many were lost, but eventually the combined forces of Qatif overtook the Mindflayers and drove the remaining forces into the center facility of the Elder Brain. With the glass dome being all but impenetrable, it took the force of the remaining bomb to punch a hole in the dome wide enough for The Shards of Khaios and a few dwarven forces to breach the Elder Brain's lair.

Elder Brain
Inside the dome, the Shards encountered various abberant creatures that acted as a last line of defense for the Elder Brain, among them being aboleths and gibbering mouthers.

Appearance
The large cave they dwell in is mostly comprised of dark or dim lighting, with a few bright spots here and there. A few drow or tieflings can be seen once in a while, but mindflayers make up the very vast majority of the population. At the very center of the colony is a massive glass dome, although the glass is opaque and difficult to see through. This dome is known to hold the Elder Brain. The dwellings in the colony are small and barren, serving the sole purposes of storage, and a safe resting space. There seems to be no coherent organization or layout to the colony, it is simply a large mix of dwellings and the occasion shop.

Government
From the brief time the party spent in the city, they gleaned that there is a leader and government of some sort, although further details were not obtained.