Unlike Winter Assault, Dark Crusade is a standalone expansion that does not require prior installation of Dawn of War or Winter Assault to play, allowing the user to play as all seven factions in both single player Skirmish and Campaign modes. Including the Imperial Guard from Dawn of War 's first expansion pack Winter Assault, a total of seven playable races in this expansion. The expansion features two new races, the Tau Empire and the Necrons.

Based on Games Workshop's tabletop wargame, Warhammer 40,000, Dark Crusade was released on October 9, 2006. Warhammer 40,000: Dawn of War – Dark Crusade is the second expansion to the Real-time strategy video game Warhammer 40,000: Dawn of War developed by Relic Entertainment and published by THQ.