Arthur Gannon is an Enclave officer tasked with tracking down the mysterious package known as HR-D4. He tracked this package through the Commonwealth until he discovered its location at the FMS Columbia. There, he and a few other soldiers attempted to uncover HR-D4, but he was captured and his fellow soldiers killed by Janus. He was put into a cage alongside the captured HR-D4, and he eventually died of his injuries. He can be found in the cell right next to the player at the start of the game.