A Reddit user posted an image that showed some new secret characters after said person downloaded a test DLC from the Developers server for Mass Effect 3.
The characters shown are the Batarian Soldier, Geth Infiltrator, Geth Engineer, Batarian Sentinal, Krogan Battlemaster, and Asari Justicar classes to be used in the multiplayer portion of the game.
A lot of people are speculating that these classes will be tied-in with the upcoming Mass Effect 3 action figures. Bioware has yet to confirm these claims.
Thanks, Game Informer.