Galen Erso is a fictional male in the Star Wars series. The character was portrayed on screen by Mads Mikkelsen. His allegiance / loyalty is to The Galactic Empire. Galen Erso was a father and a husband who was hiding out on a remote planet called Lah'mu away from the attentions of the Galactic Empire as a farmer. Galen was a genius engineer who had been involved with the Galactic Empire building their technology but whom had grown disillusioned and wanted out. Galen left the Empire and settled for a simple life on a non-industrialised planet,
Galen Erso was discovered by Director Krennic who took him back to the Galactic Empire to work on the nearly finished Death Star spacestation. Galen's wife Lyra Erso was killed when Lyra tried to fight off a group of Krennic's black Stormtroopers to no avail. Galen's daughter, Jyn Erso hid after witnessing her mothers death. The Stormtroopers were unable to find Jyn and left without her.
Jyn Erso hid in a shaft and was found by Saw Gerrera and looked after until she was sixteen and then essentially deserted to fend for herself. Jyn would later confront Saw to find out why she was abandoned by Saw those many years ago.
Galen called his daughter Stardust, a term that would later allow Jyn to work out where the plans for the Death Star was located in the main computer storage area.
Galen struggles with the knowledge that he has created a weapon of such immense power and destruction. People will draw parallels with J. Robert Oppenheimer, the American most associated with developing the Atomic bomb where two were unleashed on the Japanese as Hiroshima and Nagasaki during the last days of the Second World War in 1945. Clone Corridor
Galen perusades the Imperial pilot Bodhi Rook to smuggle out a message for the Rebel Alliance. In the message is a warning to the Rebels about the Death Star and what it can do. Galen also reveals to the Rebels about the way to destroy the Death Star. Galen had put in a small unnoticable fault in the designs that would allow the spacestation to be destroyed by a surgical strike. A strike that would be carried out in Star Wars IV - A New Hope by none other than Luke Skywalker.
When Director Krennic discovers that someone has been feeding the Rebel Alliance information, he visits Galen Erso at the Kyber Crystal Refinery on Eadu to find out who the person is. Krennic orders that the person reveals himself or the scientists will be shot. Galen is saved from being in the firing line but when Galen reveals himself to be the person who did the leak, Krennic opts to spare Galen's life and instead kill all the other scientists on the project.
Galen is killed during a strike on the Imperial refinery base on Eadu when it is attacked by X-wing. Jyn never got to see her father alive to talk to, she only saw him die after the attack by the X-Wings.