Galen Erso is a fictional character from the Star Wars universe, primarily featured in the film Rogue One: A Star Wars Story. He is a skilled scientist and engineer known for his work on the Death Star, the Empire's superweapon. Galen's expertise in energy and weaponry makes him a key figure in the development of this destructive technology. In the story, Galen is portrayed as a reluctant participant in the Empire's plans, having been coerced into working on the Death Star project. He ultimately seeks redemption by secretly including a critical flaw in the weapon's design, which becomes pivotal for the Rebel Alliance's efforts to destroy it.