Which Xbox franchise features the fictional planet Sera as its main setting?

The Gears of War franchise features the fictional planet Sera as its main setting.

The series follows human soldiers, especially members of the Coalition of Ordered Governments, during their war against the subterranean Locust Horde and later the Swarm. Sera is a technologically advanced world whose societies and landscapes are reshaped by decades of conflict.

The original Gears of War, released for Xbox 360 in 2006, introduced Marcus Fenix and Delta Squad. Later entries expanded the setting's history, including the Pendulum Wars, the Locust emergence, and the aftermath of the Locust War.

Sera is sometimes confused with the settings of other Xbox-associated science-fiction franchises. Halo primarily takes place across multiple planets and installations, including the human world Reach and the ringworlds called Halo. Gears of War remains specifically tied to Sera and its human-versus-Locust conflict.