The Imperium

The Imperium is the oldest remaining empire in the galaxy and consists of hundreds of thousands of millions of worlds, athough younger than the long lived Eldar and Necrons. The Imperium is so massive that it's almost impossible for any response to a threat to be made quickly. The usual response time is within a century or two. From The Space Marines to mighty Titans, the Imperium of Man will conquer all.

There are numerous types of armies that serve the Imperium: from the numerous Imperial Guard, to the Space Marine super soldiers, The sisters of battle, and many others.