Gears of War has sold more than 3 million units and is the most popular game on Microsoft's Xbox Live service, which allows players to compete against each other online. Though released in November and available only for the Xbox 360 console, it quickly became the fourth-bestselling game of 2006 in the U.S.
The story, which is only modestly developed in the game, concerns a world reeling from an invasion by aliens known as the Locust. A small group of elite soldiers, including main character Marcus Fennix, who is rescued from prison at the beginning of the game, fight to retake the planet Sera for its surviving humans.
Epic developed an extensive backstory in hopes of utilizing it for a film as well as potential novels.