The Codex gathers the canonical Games Workshop background this project builds on — kept separate from the fan-made Successor Chapters and stories. Five archives, each searchable on its own:
- Worlds — canonical planets and sectors.
- Legions — the Space Marine Legions of the Great Crusade era.
- Successor Chapters — canonical Successor Chapters from Games Workshop.
- Characters — canonical personalities of the Warhammer 40,000 universe.
- Reference — further canonical terms and relics.