"Fetch me another play thing this one is broken" -Uiren Rekarth

__At the height of Eldar civilisation, the ancestors of today's craftworld-dwellers considered themselves godlike. The race was the undisputed master of the stars from the galactic core to the western rim, a hundred thousand years in advance of their primitive neighbours whom the Eldar considered little better than savages. The story of the Fall of the Eldar, of the creation of the chaos god Slaanesh and the destruction of the homeworlds, is still told among those who survived, as a warning of the dangers of chaos.
__ But the proud Eldar have secrets still, and there are parts of the story they will not tell. These tales are held only in the Black Library, guarded by the Harlequins of the Laughing God, and they tell of those whom the craftworlders left behind when they fled their worlds, whom they believed destroyed in the birth of the Great Enemy. Only later, too late, did they discover that their ancient brethren left to die had survived, and returned to exact vengeance.
__The story of the Dark Eldar began on the first and greatest homeworld of the Eldar race. The world was the hub of Eldar civilisation, a massive structure formed of twin planets joined together by a great bridge in space. The giant city-world, home to a million billion people, was the remnant of a time when the young Eldar race was still fearful of attack from the then-unknown depths of the void. The natural resources of both worlds had been sacrificed to create this impenetrable bastion, where the Eldar would be safe from any enemy even if the other homeworlds fell. It was called Fortress - in the ancient Eldar language 'Commorragh.'
__In the decades before the Fall, when the Eldar civilisation turned inward in a self-destructive orgy of blood and death, Commorragh was for many years the last refuge that resisted the tide of destruction. It was here that some of the greatest of the craftworlds, Iyanden, Alaitoc and Lugannath among them, were built in the three-hundred-mile long spacedock and launched into the endless night. Finally, as had all the other homeworlds, Commorragh descended into madness.
__The rulers of the blood-soaked city-world, determined to survive the immenent destruction of the Fall, began to search for an escape, a way to flee or fight the creature that would soon consume their worlds. In desperation they scoured ancient records from the dawn of their civilisation, uncovering long-forbidden weapons and devices whose very nature had been so terrible they had been buried for a hundred centuries. Among them they found the first attempts at creating a webway gate, and began to experiment. Finally a refuge was found: a dimension parallel to the warp, where the Great Enemy would be powerless to pursue them. Psychic probes found this dimension to be a void, with no matter, no space, no time. Plans were formed to create a giant portal to this new space, using the massive energy reserves of the city-world to shift itself out of this universe.
__With no time left to them, with the beginnings of the Fall already tearing at Commorragh's psionic shielding, the portal was opened. As planned, the twin world was enveloped in energy, both in realspace and the warp, and disappeared. Moments later the Great Enemy was born, and the remaining homeworld were consumed in the fire of the Eye of Terror.
__Commorragh emerged into its new space as a twisted nightmare image of itself. In this space, where the physical structures of realspace were merged with the psychic patterns of the warp, the pressure of the billions of Eldar minds reshaped the city-world in an instant, creating the Dark City as a mirror of their own souls. Water became blood, metal turned to bone, fires danced across the crystal towers, now formed of pure solid darkness.
__If Commorragh had been changed by its escape, to the rulers of the former world it now offered up the ultimate prize: eternal life. Though experiments had been done in extending the lives of Eldar beyond their natural length, these had never truly been successful. The souls of those whose time had run out lacked the vitality of younger souls, and there had been no way, even for the Eldar, to reach into the warp and revitalise a soul. Here, without the restrictive separation of the material and psychic spheres, the Eldar found they could simply extract the soul from one being and transfer it into another, using the life-energy of others to keep themselves alive. In the first years of Commorragh the Eldar there preyed on each other ceaselessly, until they realised that to prolong their own lives they required more souls than could be provided by their own race. It was then that they looked back to the universe they had escaped from, to the billions upon billions of souls that waited for them there. A year later, the primitive world known to its scattered inhabitants as Krekkal was shrouded in darkness. When the artificial night cleared, the world was lifeless. This was the beginning of the Dark Eldar.