Those among the Eldar who saw the foulness that corrupted their people for what it was became known as Exodites, fleeing to found colony worlds on the fringes of the Eldar empire. As the Eldar civilisation slid further into anarchy, others repented of their ways and left the central worlds of their empire to settle in the outlying regions of the galaxy, where they built great worldships called Craftworlds.
End of the Age of Strife
Mankind is brought to its knees by the onset of Old Night in in the 23rd Millennium, and this horrific state continued for nearly six standard millennia. By the 29th Millennium, the raging Warp Storms began to abate. When humanity finally started to emerge from the long darkness, it was forever altered. This heralded the end to the Age of Strife. Science was no longer the answer for much of Mankind, but something to be feared.
The Emperor of Mankind creates His earliest known template for genetically modified warriors. These proto-Astartes, or Thunder Warriors, will help aid him in His conquest of Terra under one ruler. The Thunder Warriors were the first gene-enhanced warriors created by the Emperor and served as the precursors to the present-day Space Marines. Wrought to be living weapons, the Thunder Warriors were known to be physically stronger, more savage and more potent in combat than the later Astartes, though they were not as long-lived. It was against this background of techno-barbaric warfare that the first Space Marines were created and the first class of Space Marine Power Armour developed.