Mass Effect

Mass Effect is a action/role-playing game created by BioWare for the Xbox 360 and PC. Players take the role of Commander Shepard, an elite member of the human military operating in the year 2183. Shepard must gather together a crew of humans and aliens in order to stop an intergalactic threat known as the Reapers. The sequel, Mass Effect 2, takes place two years after the events of the first. Shepard is recruited by a secret organization to investigate the disappearance of human colonies.

At the beginning of the game players may change Shepard's gender, first name, personal history, and appearance. The game has a morality system, although it is less about good and evil; instead, it uses two gauges representing Paragon (law-abiding and idealistic) and Renegade (ruthless and pragmatic) levels. The two are not mutually exclusive and most players end up as a balance between Paragon and Renegade by the end of the game.

Both games offer the opportunity for Shepard to become involved in romances with crew members. The first game offered three potential partners: a male human, a female human, and a female (but technically genderless--long story) blue-skinned alien (who could be romanced by both a male and female Shepard). The second game offers three partners each for male and female Shepards, although there is no longer a main same-sex romantic partner.

Mass Effect and the PPC
Due in large part to the many romantic options in the game, a great deal of Mass Effect fanfiction revolves around pairings. There seems to be a fair split between slash and het pairings. Mary Sues are less common, but they do appear from time to time. Replacement Stu/Sues of Commander Shepard are difficult to determine since he/she is a blank slate whose personality, past, and inherent abilities are all determined by the player.

There have been unconfirmed reports that the Department of Sufficiently Advanced Technology has been experimenting on technology from the Mass Effect universe. No known agents from the Mass Effect universe are currently serving in the PPC.