Starkiller, born Galen Marek and also known as The Apprentice, is the fictional protagonist of the Star Wars: The Force Unleashed video games and literature, part of the now non-canonical Star Wars Legends expanded universe; however, his first appearance was as a guest character, alongside Darth Vader and Yoda, in the fighting video game Soulcalibur IV. He is voiced by and modeled after actor Sam Witwer, who would go on to voice other characters in Star Wars expanded media, most notably Darth Maul and Emperor Palpatine.

Within the fictional Star Wars universe, Galen Marek was born as the son of a fugitive Jedi during the early reign of the Galactic Empire. When his father is tracked down and killed by Darth Vader as part of the Empire’s «Great Jedi Purge«, the latter discovers Galen and, recognizing his potential as a powerful Force user, takes him to be raised and trained as his secret apprentice, giving him the codename «Starkiller». Years later, Vader uses Starkiller as his personal assassin, sending him on missions to benefit the Empire, as well as his own plans to overthrow Palpatine. Once Starkiller outlives his usefulness for Vader, he is betrayed and left for dead, prompting him to become a Grey Jedi and join the recently-formed Rebel Alliance. Although the first The Force Unleashed game ends with Starkiller sacrificing himself for the Rebellion, the sequel reveals that Vader later cloned him in an attempt to create the perfect, obedient apprentice. The Force Unleashed II follows a clone of the original Starkiller who escapes Vader’s restraints and goes on to join the Rebellion in the fight against the Empire.

The first game’s downloadable content follows a different incarnation of Starkiller, continuing from the events of the game’s non-canonical ending. In this alternate timeline, rather than giving his life for the Rebellion, Starkiller murders Vader and is severely injured during a confrontation with Palpatine. The latter saves his life by putting him in a suit similar to Vader’s, but only so that he could serve as his new apprentice. Now known as Lord Starkiller, he becomes instrumental in helping the Empire eliminate the Rebellion over the following years, during alternate depictions of the events from the original Star Wars trilogy. Similarly, the second game features an expansion in which an evil Starkiller clone loyal to Vader and dubbed «the Dark Apprentice» hunts down the Rebellion’s leaders during an alternate depiction of Return of the Jedi.