The Deus Ex games are first-person shooter, cyberpunk role-playing games. They revolve around the character JC Denton, a bio-mechanically modified superhuman employed by UNATCO, the United Nations Anti-Terrorist Coalition, and take place in a dystopian near future in various cities around the planet, including New York, Hong Kong, Paris, Cairo, and Antarctica. The player acts as JC Denton in Deus Ex, while Deus Ex: Invisible War puts you in the shoes of Alex D, who lives in a future inexorably altered by JC's choices from the original game.
The Deus Ex franchise is laden with conspiracy-orientened storylines involving the government, secret societies, and other powerful organizations. The stories force the player to discover the truth (which usually leads to the relativist conclusion that truth is a contingent condition), forcing the player to make moral choices in order to proceed. Although the player's progression through both games is linear, the Deus Ex games, especially the first one, employ a so-called sandbox level design which allows the character to reach the end of a given area in any way they choose. A classic example comes in the second level of the first game, where the NSF, a homegrown terrorist organization, has taken several New Yorkers hostage and strapped them to explosives. The options are numerous: you can go in guns blazing and try to kill the terrorists before they trigger the bomb, you can climb down a subway ventilation shaft and drop in behind them, you can buy an EMP grenade and short-circuit the lasers that trigger the bomb, or you can just let the hostages die. The choice is up to you.
In May of 2007, Eidos announced that they were developing Deus Ex 3. Fans reacted with a typical mixture of excitement and carousing. The protagonist will not be a Denton, and instead will be Adam Jensen, a security expert for a biotech firm who is drawn into a web of conspiracy, eventually leading up at the game's end to the formation of UNATCO.
Warren Spector, the creator of Deus Ex, is not involved with the development of Deus Ex: Human Revolution since he left the franchise in 2004. He did however express interest in continuing with the Deus Ex series if given the chance but unfortunately, Eidos has refused to sell the IP to him. Spector's reaction is to create a 'spiritual successor' of Deus Ex and has pitched the idea to Disney, much like Ken Levine with BioShock and System Shock 2.
The title Deus Ex is derived from the Latin expression deus ex machina, which means 'God from the Machine.'