Gears of War: E-Day serves as a prequel to the franchise

Gears of War: E-Day serves as a prequel to the established franchise, set 14 years before the original game during the Locust invasion of the planet Sera. The narrative explores the beginning of the war against the Locust Horde, following a younger Marcus Fenix and Dominic Santiago as they transition from the Pendulum Wars into a desperate struggle for survival.

Reviewers note that the game avoids simple fanservice in favor of a serious, militaristic tone with increased elements of horror and emotional weight. The campaign focuses on the terror of the initial invasion, depicting the scale of the Locust emergence in populated urban areas. New characters introduced to the story include Lucas Reyes and Mags Carter.