"Starkiller," originally designated as Subject 1138, was the codename given to a clone of the late Galen Marek, the secret apprentice of the Sith Lord Darth Vader and founder of the Alliance to Restore the Republic.


When Marek died in 2 BBY, shortly after the formation of the Alliance, Vader endeavored to recreate his disciple by utilizing the cloning technologies of the planet Kamino. The accelerated cloning process—an enhanced version of the Kaminoan method which allowed for a rapid growth rate within its subjects—was initially imperfect and many clones were too unstable to take Marek's place as the Dark Lord'snew apprentice. After months of failure, one particular clone impressed Vader enough for him to hope that this version might become the first success. But as with the others, he inherited Marek'spower and skills at the cost of receiving his emotions as well, a side effect of memory flashes used in the training process.


Like those who came before him, the clone could not free himself from the emotional imprints passed on by Marek, especially his personal attachment to Captain Juno Eclipse, a former Imperial pilotstationed on Marek's starship, the Rogue Shadow. As with Marek, the clone's dedication to the dark side of the Force was undermined by Eclipse as he steadily became obsessed with her. When Vader judged him to be another imperfect copy, the clone escaped from Kamino and embarked on a personal journey to find Eclipse.


Lacking a name of his own, and refusing to take the one that belonged to his template, he was subsequently known by Marek's callsign "Starkiller." Immediately after his escape from Kamino, Starkiller's first stop on his quest was the planet Cato Neimoidiawhere he rescued General Rahm Kota, Marek's informal Jedi mentor. During this process, which took place in the city of Tarko-se and itsarena, the clone single-handedly incapacitated the massive Gorogbeast that belonged to Baron Merillion Tarko. His desire to find an identity for himself led him to Dagobah, where a brief encounter with the revered Jedi Master Yoda and an epiphany allowed him to glimpse into the future.