PROXY is a holodroid of unknown origin. However, he was given to Starkiller as a companion, and to assist Darth Vader's secret apprentice on his missions. PROXY is furnished with one-of-a-kind technology that lets him change his appearance to be anyone he wishes. This skill makes PROXY unique, and also incredibly valuable. Over the years, PROXY has developed a personality, and a strong friendship with his master. However, Darth Vader, in a cruel test of his young Padawan, programmed PROXY with the primary directive of attempting to kill Starkiller whenever possible. The droid will often take the form of Jedis, such as Obi-Wan Kenobi, in an attempt to end his master's life, not realizing that doing so will forever end their friendship.
He made his final attempt to kill Starkiller in the form of Darth Maul on Raxus Prime. His primary programming was deleted during the battle. He was later destroyed by Darth Vader after taking the form of Kenobi to distract Vader and allow Starkiller to escape.