Board Thread:Warhammer 40k General Discussion/@comment-95.148.187.34-20130120214333/@comment-86.162.82.201-20181024095642

The Slaves to Darkness page opens with

"In the incalculably distant past, the World was visited by the starfaring race know as the Old Slann. Their degree of scientific advancement caused some of the species they met to worship them as gods, while others reviled them as demons. The Old Slann performed many scientific experiments on the World, and although the knowledge of their presence is lost in the present day, many of the races which inhabit the World found their origin in these experiments."

'The World' referred to is the Warhammer FB world, and the page goes on to detail the use of the warpgates at both poles then falling to inactivity. It also goes on to discuss the influence of Chaos on the World and lastly mentions the taint spreading across the Imperium too, showing that the two systems did exist in the same universe. It finishes with:

"And in warpspace, the primal void of Chaos, the beings of Chaos still wait and spread their taint across the Imperium and the universe. Warp creatures hover around the vulnerable psykers of humanity, seeking a path into existance through an unprotected mind. Every psychic is a potential gateway from the void of the Warp, an unwitting agent of Chaos to be filled with a terrible power. Only the vigilance of the Emperor's Inquisition protects Humanity from the threat within itself.

And even within the Imperium there are the foolish and weak-minded who turn to the darkness. By embracing the power and horror of warspace, all that they desire will come to pass..."

Obviously as it's been said there have been a few retcons since then (I really liked the idea of the Sensei :, but that's the statement as it was in the original Slaves to Darkness.