Galen Marek (codenamed Starkiller), Darth Vader's secret apprentice was trained in the Dark Side to hunt down the surviving Jedi. Later he must decide to stay in Dark Side or turn to the Light Side.

During hunting down the survived Jedi, Darth Vader accidentally met the force-sensitive boy. The Dark Lord grew him up and trained him with the training-program-droid named Proxy. Once ready, the secret apprentice was given the codename "Starkiller", with the assignment to hunt the Jedi. When the Emperor knew the existing of Starkiller, this caused Vader to betray his apprentice- leading to the change of Starkiller's destination.—Samart Laicheewa