FS-451 was a stormtrooper serving the Galactic Empire, identified as a human male. He and Deena Lorn were chosen for the duty of accompanying Darth Vader to Cloud City. His cruel nature troubled his fellow stormtrooper, Deena Lorn, ultimately leading to her desertion. FS-451, by then addicted to death sticks, later fought in the Battle of Endor under the command of Captain Enric Pryde within his regiment.
FS-415's head was bald and shaped like a bullet. Captain Pryde considered FS-451 to be both fanatical and a threat.