X-3 was a Human male assassin who, along with six other men, was hired to participate in Project Omega. The operation was an experiment by Commander Rezi Soresh to create the perfect assassin who would then go on to serve the Galactic Empire. Soresh wiped the participants' identities from a computer database system and had their faces surgically altered. Soresh put them through a brutal reconditioning program, which was designed to turn them into mindless servants by removing their memories and emotions.
At first, X-3 became friends with X-1, X-2, X-4, X-5, X-6, and X-7, the other participants in the training program. However, after Soresh started torturing them with electrocution, X-3, like everyone else, had his personality and mind changed completely until he felt no emotions. Around 10 BBY, the would-be assassins were pitted against each other until only one remained. Despite X-3 being Soresh's personal favorite to win, X-7 killed X-3 with a vibroblade and earned the right to become Soresh's personal assassin.
X-3 appeared in a flashback sequence in Rebel Force: Target, the first book of the young readers series Star Wars: Rebel Force, published in 2008 and written by Alex Wheeler.
X-3 appeared in a flashback sequence in Rebel Force: Target, the first book of the young readers series Star Wars: Rebel Force, published in 2008 and written by Alex Wheeler.