: PDF formats allow for rapid updates, errata, and balancing that physical print media cannot match. Preservation

: Sets rules for forming alliances, treaties, and determining realm colors and home grounds. 2. Warhammer 40,000 (Historical & Fan-Proposed)

If you are a , the Codex Imperium PDF is a 4/5 star resource for lore depth, but be warned that it is a fan-project and not an official source.