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. The war began after Hive Fleet Leviathan (the biggest Tyranid fleet ever) arrived from Segmentum Pacificus. This is during another event in the timeline called the Indomitus Crusade, in which Ultramarines are being deployed to try to reunite the planets of the Imperium of Man. This explains why Titus is an Ultramarine again and why his squad is being put up against hordes of Tyranids and the forces of Chaos to defend the Imperium.
In the prologue, Titus was in the Deathwatch Chapter before returning to the Ultramarines.
In this period, a lot is going on with the long-dormant Roboute Guilliman (the Primarch of the Ultramarines and thirteenth son of the Emperor) awakening to essentially take command of the Imperium and try to return it to its former glory. As the Primarch of the Ultramarines, Guilliman assumes
Fighting
UPS
Man
Waters
War
Investigations
Universities
Horus Heresy