Total War: Warhammer 40,000's Space Marines will have to keep the Imperium happy and avoid looking too heretical

In Total War: Warhammer 40,000, the Space Marines and Astra Militarum are two branches of the same military, unlike in most historical Total Wars where factions are comparable with nations. During a demonstration at Gamescom, the Ultramarines, the Space Marine faction, experienced their settlement garrisoned by ordinary soldiers from the Planetary Defense Force.

These units only served to defend the settlement, unlike the Space Marines themselves, who could be recruited. Creative Assembly's battle product owner, Dave Petry, emphasized the importance of the Imperium's workings and the relationship between the Space Marines and local planetary forces. Petry hinted at the possibility of bringing in support units from the Planetary Defense Force or the Astra Militarum to fight alongside the Space Marines.

Additionally, a reputation system is being considered, where Space Marines must avoid actions that appear too heretical or empire-building. The goal is to fill the galaxy with various elements of the Imperium, including other Space Marine chapters and xenos threats. Unlike Total War: Warhammer, Total War 40k will be a sandbox game that Creative Assembly will continue to expand, rather than separate games.