PROXY was a prototype holodroid who served as a companion and long time friend of Galen Marek and traveled with him on the Rogue Shadow. Despite their friendship, PROXY would routinely try to kill Marek during training as this was his primary directive provided by Darth Vader.
After Marek sacrificed himself for the Rebel cause, PROXY served under Captain Juno Eclipse, Marek's lover and former pilot of the Rogue Shadow.
PROXY was equipped with advanced hologram technology that, when coupled with his built-in servos, would allow him to change appearance and adopt a wide range of disguises. He could also present messages: he would create a holographic representation of the sender, and the sender would say the message. Also, when Galen wanted information on an individual, PROXY would turn into that person and access databases to confirm his/her identity. He was also capable of holding his own in lightsaber combat against Marek for a short time.