Resident Evil 6 boasts 4 different campaign modes, each with different lead characters. As reported by Gamespot, the fourth character available for play in the upcoming survival-horror shooter is Ada Wong, a villain who also assists Leon S. Kennedy.
Ada’s campaign will allow you to wield a crossbow while taking down enemies in a dominantly puzzle-based setting. Unlike the other campaign modes, Ada’s campaign is strictly single-player, allowing no multiplayer co-op. Though there are sections where you will play with AI-controlled partners, Ada’s experience will only let one human player in. Also, you will need to finish all the other campaigns first in order to play through Ada’s section. You’ll be going through locations and events that have already transpired in the other characters’ stories while playing as Ada, so think of it as a sort of “additional/deleted scenes” perspective in some locations. Still, Ada’s fights will have hordes of monsters and large boss fights, along with more information about her sister, Debra.
Those looking forward to Resident Evil 6 can grab it when it releases on October 2, 2012. You can also see the full Gamespot article with some gameplay videos here.