He finds himself assigned to the Terminator company. The player is one such Space Marine, belonging to one of the oldest and most honourable Chapters known as the Blood Angels, whose battle honours date back as long as the Imperium has existed.

The defenders of the Imperium are the Adeptus Astartes, or Space Marines, bio-genetically engineered warriors of superhuman prowess, ever vigilant to destroy the many threats that face mankind across the cosmos. Under the auspices of the Emperor a psychic so powerful he is essentially immortal, a pan-galactic Imperium has been established in which mankind has spread and prospered.

For 20,000 years mankind has expanded forth throughout the galaxy aided by a phenomenal invention known as the Warp Drive, which allows huge spatial distances to be traversed in a matter of hours.