Return of the firstborn

For untold eons they remained forgotten. Discarded by their creators like a child tossing away an old toy in favor for a newer one. They were the real heirs to the old ones and for too long have they watched the false ones despoil their inheritance.

Excerpt from the prophecies of farseer Gra'ssex

After their supposed victory over the leviathans the eldar empire was at last uncontested by any other force in the galaxy. Their unfettered access to the webway allowed for them to rapidly expand until their core worlds encompassed a mind boggling 10000 light years space , that's without adding the untold number of outposts, maiden worlds and webway ports.

The eldar rule over the other races was fairly benevolent (or at the very least not actively malicious) ; So long as they swore allegiance to the eldar, paid tribute and didn't stir up any trouble they were allowed to do as they wished, in return they were protected from the never ending tide of the orks.

The greenskins had become a galactic infestation of immense proportions. Hundreds of planets moons and even asteroids became incubators for trillions of various orkoid organisms that would grow into WAGHHs of incalculable sizes. Some of these would even manage to fight off the Eldar extermination fleets and would prove to be a nuisance for the knife ears.

Still these were 'minor' skirmishes compared to the horrors of the War in Heaven and the enslaver conflict. The Galaxy was relatively at peace (at the very last it wasn't threatened with complete annihilation).

It was during this era that the eldar reached their apex but in their dominance they grew decedent. It is known that eldar experience emotions at a higher intensity than any species as a result of their greater connection to the warp. And the emotion most prevalent at the time was sheer inescapable boredom ; there was no enemy that wasn't easily defeated and broken, nor was there any need for tiresome labor( which was performed by machines ) .

Without anything else to fill the void in their souls the children of Isha turned to hedonism and depravity to fill the void in their souls. It started benign enough ,but slowly and gradually their activities become ever more callous and depraved.

Stars were stolen from their systems for the sheer barbaric amusement of watching races hopelessly die, depraved cults that catered to any twisted fantasy the knife ears could imagine and more, sprang up on every world where the knife ears lived. Very few eldar records survive from this era (though it would be more accurate to say that they are inaccessible as the remaining craftworlders jealously guard any lore they have left and it is doubtful any of these records survived the burning of the Dark City) but what we do have paints a terrible picture of the eldar empire.

However the eldar were being watched from the shadows. The Protheans, the rejected heirs of the Old Ones had watched as the unworthy vermin that replaced them defiled and twisted the galaxy that should have been rightfully theirs.

The Protheans had come a long way since they were abandoned and left to languish in obscurity on an unremarkable world, for they had been stripped of all technology and devolved to a primitive state. Eventually however they managed to claw their way back into civilization ; unfortunately as they began to reach out to the stars they faced a connedrum. Protheans were all psykers, not patcurialy strong but enough to allow them a psychic field , not unlike the orks, that connects them, allowing for their unparalleled cohesion and coordination in battle.

Unlike the greenskins this field did not come with the added bonus of protection against warp predators and the corruption of chaos. This proved to be troublesome for the early protheans who had to contend with many daemonic incrusions , eventually as their culture grew to value discipline the attacks lessened both in severity and frequency. However in the warp, the souls of the four eyed xenos were luminos and tempting to the neverborn, drawing in some of the oldest foulest creatures that were motivated enough to break through any geller shielding.

This meant that warp travel was suicidal for the protheans and it seemed their expansion would stop before it began. But a solution was found : element Zero. The material was abundant on the nameless planet the protheans called home and wasn't seen as useful for anything other than randomly causing biotic potential. But a brilliant prothean scientist managed to create the first Eezo drive -based on how biotic used their vanguard abilities.

This new form of FTL allowed for the protheans to rapidly expand unchecked by the whimsical tides of the warp though mass effect ships were slower and their eezo requirements meant they were smaller, at least at first and until numerous bountiful deposits were found.

Their bitterness at being abandoned by their "gods " led them to becoming imperialists that conquered any species they encountered with the only choice given is "submit or be broken " .

In a relatively short time their empire had grown exponentially but it was still dwarfed in magnitudes by the eldar empire in all aspects which the protheans discovered in the 49th millennium PF (preceding the Fall.

The Orvaroes were a resource hungry and expansionist species , always looking for more planets to colonize and exploit and they were doing just that on a planet that would later be known as Thessia.

Unknown to them it was also discover by Prothean probes, months prior and a colonization fleet was on the way, which was accompanied by a similarly sized defense flotilla (incredibly costly but the four-eyed species spared no expense to ensure speedy interstellar growth). The Orvarion colonists were given the choice to kneel. They refused and where killed to a man and the survivors forced into indentured servitude.

The Orvarians were furious and relayed these events to their eldar masters , the eldar retaliated, not out of an concern or real outrage but out of curiosity and boredom.

The Aldarei contacted the protheans and demanded that the protheans either submit or be exterminated and the protheans chose to resist much to the knife ears delight who found a new source of entertainment.

The Protheans in their arrogance believed themselves to be above all other species and that their destiny was to tame the cosmos to their will and faced the eldar with the belief the Eldar, who had usurped their right, would be defeated quickly.

They were wrong.