Aboleth

Ants have grand plans. They build elaborate structures over the course of generations. From an ant's perspective, their societies are complex and eternal. They aren't. They're mounds in the sand, and the sea comes to wash them away. The sea is eternal and it washes away their pathetic homes. I am the sea. You are less than ants.

Now beg for me to kill you like your friends did.

-Molmig the Permanent, an aboleth killing a group of adventurers its favorite way - mentally impelling them to beg for death

Introduction
Aboleths are among the most sinister and horrible of all threats to sentient humanoid life. Ancient, immortal, and all-knowing, aboleth are primeval abominations fueled by inhuman arrogance and hate for all other beings.

Physiological Observations
Aboleths are the oldest sentient life in existence. Their basic body shape resembles an eel, although not even a blind old fool could mistake an aboleth for any natural modern animal. They have no fins beside on their tail and down their back. Behind their head, four muscular tentacles twist and turn. Three huge red eyes - vertically arranged - sit at what would be called their face, above a mass of tentacles. The tentacles pull food into the aboleth's small, slit-like mouth.

Along the side of their body, aboleths have huge, gaping holes. These are roughly an analog to nostrils or gills. Aboleths breathe and vocalize through these holes. Aboleth language is enormously complex - it covers a vast range of pitches, clicks, croaks, pops, and sing-song esque vocalizations. Even with a lifetime of training, a humanoid mind is incapable of grasping any but the most basic meaning an aboleth expresses.

These holes also produce the aboleth's distinctive slime. This filthy muck turns the water around an aboleth into a thick, soupy mass. The aboleth requires this slime to breathe and to maintain moisture in its brief forays above water. The slime can also infect other creatures, forcing air breathing creatures to breathe water. The aboleth transmits this disease using its tentacles.

When one speaks of the dawn of time, they are referring to the first memories of the aboleths. This memory is no myth or folklore passed down - it is a simple fact that every aboleth remembers in perfect clarity. An aboleth has a perfect eidetic memory - it can recall every instant of its entire life in exact detail. These memories tretch back a long time, because once an aboleth reaches adulthood it ceases to age - they are immortal except for violence. But even more significant is that an aboleth's memory is passed down to each generation.

Aboleths reproduce asexually. Every few decades, an aboleth retreats to a secure location and lays a clutch of of 5-10 eggs. The aboleth doesn't move from the eggs for any reason until several weeks have passes, at which point it "swallows" the eggs with the holes on the side of its body. After another month or so, the aboleth vomits out fully developed but smaller aboleths - the young are called smiluts. They're only a few feet long at birth, but mentally fully developed and carrying all the memories of their entire familial line. They spend a year or so with their parent - there is no childhood for an aboleth, only a period of protection while they develop physically.

Aboleths also possess formidable psionic powers. They can communicate telepathically with all manner of beings and, most terrifying of all, can dominate the minds of lesser beings. They often force other creatures to serve them as thralls.

Social Observations
Aboleths used to rule a planet-spanning empire. For more than a billion years, they were the unquestioned masters of the world. They were served by advanced constructs they built, but eventually desired slaves capable of a certain degree of independence. The aboleths took fish and altered their form using dark arts and advanced science. They shaped the creatures into a form that mimicked their own. Above the surface, they performed similar experiments on apes, developing the first hominids. They let these species develop, forcing most of them into slavery and watching the others.

As their control over their subjects increased, so did their vanity. Until their subjects, in their hopelessness, created religion and brought the gods into being. The gods smote the aboleth empire and liberated their worshipers.

Now, hundreds of thousands of years later, the aboleth empire is not what it was in its heyday. Aboleths lurk in secret in the deep waters of the world. Most are largely solitary, meeting with other aboleths every few decades to further their devious plots. Aboleths, vile and alien though they are, are capable of something resembling friendship among their own, although an aboleth would never come to a friend's aid - if one is unable to protect itself, it does not deserve assistance.

A few aboleth cities exist in secret around the world. Architecture with blasphemous geometry - strange stones twisted into impossible shapes. The hierarchy is impossible to comprehend for mortal minds and their governmental systems operate over spans of millennia.

And as a rule, aboleths worship no gods - they recognize the very real power of the divine, but feel no need to prostrate themselves before something so much younger than they are.

Behavioral Observations
The primary drive for aboleths in all things is a deep hatred of mortals and gods. They remember their billion year empire and what was taken from them. Each aboleth constantly burns with a cold, alien bitterness at the injustice they perceive. They will stop at nothing to reclaim their rightful place atop the world, but they plan on a geological time scale - to the aboleths, their displacement was a recent event. It is quite possible they are still in the very early stages of their plans to regain power. This is the way an aboleth thinks.

They are immensely cruel and take great pleasure in the suffering of lesser beings. They have an almost artistic passion for the mental domination and enslavement of mortals. Some take this to levels impossible to comprehend - capturing humans from the surface and adorning the walls of their lairs with their still living bodies as a canvass for blasphemous art, forcing mothers to eat their children, and other things simply too hideous to describe.

An aboleth's lair will always be in deep, dark water. They will often be surrounded by pathetic, mewling slaves. They cover their homes in magical artifacts and alien art.

Intra-Species Observations
Aboleths have nothing but hate for all other intelligent life. But they are not fools. They acknowledge and, to a certain degree, even respect the power of gods and mortal heroes. They also understand, however, that those other powers are but a blink in the eye of the aboleths - in time, they too will fade.

Aboleths are careful to hide themselves from the world above - secrecy is paramount to protecting their plots. They interact with the world primarily through their thralls. When they do occasionally emerge to the world above, it is in a terrible unveiling of power - a reminder for the mortal world that all they know is only temporary.