Although it's perfect as a portal to the franchise's universe, is only the tip of a titanic iceberg lurking below the water's surface.
Despite originating from a tabletop game, has a hilarious abundance of lore, stretching tens of thousands of years, from when the Necrons first became robotic conquerors, to the 41st millennium, where Ultramarines are desperately trying to reunite the Imperium of Man. 's placement in the timeline isn't as obvious as one might think, and some investigation is required to figure out when exactly it takes place.
It should be noted that takes place roughly two hundred years after the first game in the series,and a few hundred years pass by quickly in with wars tending to last forever.
There are a few characters that were alive during the Horus Heresy, one of the biggest events in 's history, that ironically happened in the 31st millennium, but as far as is concerned, that is distant history.
The game takes place in modern, where humanity is having a particularly rough time. Spoilers for Space Marine 2 And Warhammer 40K Lore occurs in the 41st Millennium, during the Fourth Tyrannic War, hence why there are so many Tyranids to shoot.