In Mass Effect 3 for the PC, PS3, and Xbox 360, you can unlock the Krogan Sentinel as a character to use in multiplayer, which is a combat character trained in tech and biotics.
The Krogan Sentinel is a rare card that you can get from purchasing any of the packs, however your chances are much better to unlock characters by purchasing Veteran and Spectre packs instead of Recruit packs.
Check out my other guide for more unlockable characters in Mass Effect 3 multiplayer.
