In Resident Evil 6 for the PC, PS3, and Xbox 360, there are four primary campaigns to play through in the game, but only three are unlocked by default, which are Chris Redfield, Leon S. Kennedy, and Jake Mueller.
You can unlock Ada Wong’s campaign story if you want to play through the game as the beautiful bad ass, and completing her story is required for some of the other unlockables in the game as well.
To unlock Ada Wong’s campaign, you just need to complete all three of the other campaign stories.
Check out my other article for a complete list of cheats, unlockables, tips, and tricks for Resident Evil 6.
