Dawn of War II struck a new chord in the RTS genre with its focus on specific unit based strategy with limited reinforcement options and limited RPG elements, as opposed to the generally repetitive RTS tactic of resource gathering-base building-and swarming maneuvers. The Chaos Rising expansion to the franchise follows suit with 15 new single player missions centered on the players' strategic choice of units; upping the ante further by including new units for each of the returning in-game races and even introducing a new race, the traitorous Chaos Space Marines, who are a playable faction in online multiplayer action.