
Army of Two is a third-person shooter video game developed and published by Electronic Arts, released on March 4, 2008 for the Xbox 360 and PlayStation 3 consoles. The game is centered upon two mercenaries fighting through war, political turmoil, and a conspiracy from 1993 to 2009. Focusing on cooperative strategies, Army of Two's main feature is the necessity to use coordinated teamwork to accomplish the game's goals. While the game is meant to be played with another human as a partner, a "Partner Artificial Intelligence" (PAI) is also included and programmed to follow the player's strategies. Dependence on a partner (whether human or PAI) is so pronounced that most objectives are impossible to complete without it.

Army of Two: The 40th Day is a third-person shooter video game that is developed by EA Montreal and published by Electronic Arts for Xbox 360, PlayStation 3, and PlayStation Portable. It is the sequel to Army of Two. Army of Two: The 40th Day was released on January 12, 2010 in North America and January 15, 2010 in Europe.[5]
The 40th Day focuses on two-player cooperative play and employs a cover system. It features Tyson Rios and Elliot Salem, the two protagonists from the original game, as combatant partners who, with the assistance of their handler Alice Murray, must fight to survive and prevail over invading forces that have engulfed Shanghai, China in a devastating terrorist attack.
Army of Two: The Devil's Cartel is an upcoming third-person shooter video game developed by Visceral Games, using the Frostbite 2 engine, and published by Electronic Arts for the PlayStation 3 and Xbox 360. Army of Two: The Devil's Cartel is scheduled to be released in March 2013 and is the sequel to Army of Two: The 40th Day.
(all info courtesy of wikipedia)