40K is an alternate version of the Foundationverse galaxy where the Tilling Project was never launched.
Basically the fanfic takes place in the very early era of humanity's expansion into the galaxy in 40K (long before the Age of Strife), harmonizing this with the early Foundationverse timeline it would be maybe six or seven centuries after the events of Robots and Empire.
At the time of the Tilling Project the galaxy was mostly infested by Krork and the Eldar were just beginning their expansion (so the Orks were too disorganized to fight the Tillers, the Eldar were still too weak, and the C'tan all got blasted to dust in their sleep when their tombworlds got the Genesis treatment).
As in 40K the Tilling Project was never launched by the time of the fanfic the Settler worlds have been on the recieving end of a long series of Waughs as they expand into an Ork-infested galaxy. More seriously they've recently run into the expanding empire of the Eldar, and the two species are now fighting an endless low-intensity (most of the time) war for control of new planets and areas of the galaxy.
The Giskardians are much too worried about humanity's xeno enemies to pay much attention to Chaos Virus outbreaks. So no Giskard projectors to keep the population in line and no attempt to organize humans into a galactic society designed to resist Chaos. As a result the Chaos Virus (which is actually a Warp-related phenomenon) is gradually growing up into the much scarier Chaos Gods we all know and love as it takes power from the violent emotions/suffering of humans and Eldar. The God Emperor is likewise still in his maturation phase and won't make his presence known for a long time. As the Warp is becoming more and more disturbed instantaneous hyperspace travel is no longer possible, and ships must spend long periods of time immersed in the turbulent warp to get where they need to go.
Incidentally the Settlers have used stolen Eldar tech to reverse the radiactive poisoning of Earth, just to tie up that loose end.
All told while the historical background is Asimov's Robots series it's starting to look more and more like the bloody wartorn future of 40K all the time.
So, could it work?
