Warhammer: The Horus Heresy

The game is set in the 31st millennium during the civil war in which Warmaster Horus rebels against the Emperor. Its focus on the Legiones Astartes and the wider Age of Darkness gives it a more specific historical conflict than the broader Warhammer 40,000 setting.

Yes, it emphasizes large formations of infantry, vehicles, and tactical engagements between Space Marine Legions and other forces. The rules are designed for battles that feel like major campaigns rather than small skirmishes.

You need the core Age of Darkness rules and the army rules for the faction you want to play. Games Workshop's Age of Darkness starter guidance separates the core rules from the Legion army books, such as Liber Astartes and Liber Hereticus. [Games Workshop starter guidance](https://www.warhammer-community.com/en-gb/articles/kOPHIGL7/new-to-the-horus-heresy-heres-everything-you-need-to-get-started/)

The Horus Heresy concentrates on a defined civil war in the 31st millennium, with Legion identity, historical campaigns, and pre-Heresy or Heresy-era technology central to the game. Warhammer 40,000 is set later and supports a much broader mixture of factions and time periods.