The War in Heaven

Before mankind crawled from the mud, the galaxy burned in the first great conflict of recorded existence. The War in Heaven was fought across sixty million years, pitting the star-gods known as the C'tan and their skeletal legions of Necrons against the enigmatic Old Ones and the myriad servant races they had wrought to defend creation.

The Necrontyr, a short-lived and jealous species, had bargained away their flesh to the C'tan in exchange for immortal metal bodies. This biotransference reduced them to soulless automatons, obedient slaves to the deceiving star-gods who feasted upon their essence. United by hatred of the ageless Old Ones, the newly forged Necrons waged extermination upon the galaxy.

The Old Ones answered with legions of their own devising, gene-crafting warrior races to hold the line. Chief among these were the ancestors of the Aeldari, swift and psychically gifted soldiers born to fight a war that spanned aeons. Yet even their brilliance could not undo the tide, and worlds fell to ruin in numbers beyond counting.

In the end the Necrons turned upon their C'tan masters, shattering them into shards to be bound in servitude, then retreated into stasis-tombs beneath a thousand worlds to slumber out the long ages. The galaxy fell silent, littered with the graves of forgotten empires, waiting for the sleepers to wake and resume a war never truly finished.