The game has three modes. In the "campaign mode" the player controls the Eldar forces and follows the efforts of the Craftworld Iyanden to conquer a Maiden World, a lost colony of the ancient Eldar race. During the campaign an additional and far more dangerous foe, the alien Tyranids, emerge and the Eldar and Imperial forces unite to defeat them. In "skirmish" mode the player can play as the Imperium, Eldar or Tyranids. The Imperial forces include the Imperial Guard, the Red Scorpion legion of Space Marines, and Sisters of Battle. In multiplayer mode the player can battle other players online.