The universe is not yet in perpetual war, but the threats that will plague the 41st millennium are emerging. Alien races like the Orks and Eldar are becoming more aggressive, and the first whispers of the Tyranids are being heard at the galaxy's edge. Meanwhile, the insidious influence of the Chaos Gods is growing, setting the stage for the corruption that will eventually engulf many of the Emperor’s Space Marines.
This period is ripe for the exploration of legendary figures, those who stood as pillars before the fall into chaos. Potential heroes could include early versions of characters known in the 40k lore, as well as entirely new figures who fought valiantly against the encroaching darkness. These could be the early champions of the Astra Militarum, precursors to the Inquisitors, or even lesser-known Primarchs whose stories were lost to time by the 41st millennium.