WeirD&D: Aboleth

Born from the Fell Star, the Aboleth are primordial fish-things from the Beyond. When the Fell Star descended to the material plane, the Aboleth came with it and have since spread across the Material plane to do its bidding. Alien in shape and mind, Aboleth wield terrible psionic powers and celestial divination. From the depths of the oceans, they are the brain behind the aberration wars, created to think, plan, and remember for the Fell Star's more primitive minions.

Star-Spawned

The Aboleth are born within the heart of the Fell Star, an alien god from the void beyond the Planes. Each Aboleth is unique and they number only over 300. No two Aboleth look the same or act quite the same, each made to think and know different ways. Near immortal, the minds of slain Aboleth return to the primordial soup from which they were born to be reconstituted within the Fell Star. Depending on their age and the whim of their gods, it can take years. For the ancients among them, the process can take decades, if not centuries.

Aboleth grow by consuming magic, either from natural places in the world or objects of power. Wizards and sorcerers are prized meals, slowly devoured to extract every last spell from their flesh.
The more magic an Aboleth has consumed, the larger and more powerful they grow, while a starving Aboleth shrink and their powers wane.

Along with magic, the Aboleth possess the fearsome ability to consume memories and knowledge, adding them to their own. It is through this power that the Aboleth remembers for the Fell Star and its other minions.
The Primordial clay that crafted the Aboleth reacts strangely to the reality of the Material Plane, so the Aboleth continuously secrete a mutating mucus to protect them. The Aboleth uses the slime to remake the world around them to suit their needs or twist mortal beings into terrible aberrations and hapless servants.

Rememberers

Each Aboleth that exists has been around for centuries or even millennia. The youngest among the Aboleth have watched many mortal empires rise and fall to ruin. As such, Aboleth have an alien view on time and mortality, able to spend centuries perfecting their ploys. They can remember things that happened millennia ago with perfect clarity and recall every defeat, every victory, and every strategy. Together with their ability to consume memories, the Aboleth is the reason the aberration hordes can learn and adapt to everything put against them.

Reaching further back into the past to remember is an effort on the Aboleth parts. They sink into a meditative trance as they browse through centuries of accumulated lore, sifting through memories from a thousand different victims.

Most Aboleth stay with the Fell Star at the bottom of the ocean, staying in communion with their god and leading is hordes.
A few other strike out across the world to establish hidden covens and lairs, or to do some task at the behest of the star. A precious few are in the state of being re-created within the star.

With a perspective that span for millennia and immortality meant to remember eternity, Aboleth cannot empathize with other creatures. At best, they can use their stolen memories to approximate what the emotion means but not in any way a mortal could relate to. Even such fundamental things as fear and pain are alien to the Aboleth, to whom death is only a return to their god-womb.
When outside the Fell Star's domain, the Aboleth favors aquatic lairs where they can swim around effortlessly. They take great pains to mutate their dominion to suit their needs and alien esthetics. An Aboleth's den is a dangerous place, where warped plants each out to strangle intruders or the rock scream in alarm when touched.

To the Aboleth, the mortals of the material plane are little more than inferior insects - albeit well-armed ones.

Aboleth in the World

Aboleth are mostly seen when leading other aberrations into battle or are rooted out murky hiding places by adventurers or various organizations dedicated to fighting them. They are the agents of the Fell Star, and their actions always bring them into conflict with the other denizens of the Material Plane.

Especially us nosy adventuresome types!

— Kal'am, Adventurer and Nosy Type

Much more intelligent than most other aberrations, Aboleth knows how to use deception and subversion to achieve their goals. They sometimes cultivate cults among the surface-dwelling races or mutate unfortunate victims to create slaves. Typically, the purpose of an Aboleth's ploy is either a source of magic or a source of knowledge - the latter usually by consumption. Other times, the Fell Star makes more esoteric demands and it is the Aboleth that spearhead these incursions into the mortal lands.

by Rock Cafe.info

Rogue Aboleth aren't much better, viewing all other beings as a source of food, servitude or magic, or a danger to be dealt with. With no way of reincarnating, the rogue Aboleth cling to their lives with hideous tenacity and will do anything to preserve their lives.

The Beyond

The vast darkness that lies past the planes is known as the Beyond. Is it a nebulous space, not quite a plane and not quite a true reality. It is the void beyond existence, the edge past all things, where reality is still unformed. In this sea of infinity, things spawn in the starless void.
Unfathomable distance separates the voidspawn from the other planes, but sometimes they are drawn into reality. Driven by unknown motives or called by mad cults, the things from Beyond bring madness with them.

Aboleth don't really have names - whatever means they use to tell each other apart is alien to mankind.
When Aboleth infiltrates the lands of mortals and subverts cults to their cause, they sometimes adopt temporary titles. These are typically grandiose and based on old, consumed memories.

The Fell Star

A god-thing from the Beyond, the Fell Star has traveled the void for millennia to reach the Material Plane. The impact of the Star ruined empires and unleashed the terrible star-plague. It burrowed into the bottom of the ocean and stayed there since, like a jagged wound upon the world.
The Fell Star has only been seen a few times and is said to resemble a vast meteorite of living matter with the spiked shell of some monstrous insect. Its reason for coming to the Material Plane is unknown but is a terrible scourge for all living things.

A rare few Aboleth have broken from the Star's control and go their own way.
These Aboleth surrender their immortality and should they die, only annihilation awaits them upon their return to the Star.

The Deep Wars

To this day, the dwellers of the deep wage unrelenting war against the Aboleth and their alien god. Triton, mermen, and their assorted allies have battled the Aberrations ever since the Star first fell upon the world. The Triton calls them the Deep Wars and it still rages on in the darkest depths of the oceans.

Plot Hook

The monsters in an area are suddenly displaying unusual degrees of coordination, kidnapping sages and scholars from the local university. An Aboleth have brought them under its control and it is devouring the victim for their knowledge, in preparation for some foul plot.