U3PO

U-3PO, also known as Yoo-Threepio, was a 3PO-series protocol droid created by Cybot Galactica prior to the Battle of Yavin. U-3PO served in the Diplomatic Corps of the Royal House of Alderaan during the Galactic Civil War, but eventually became a sleeper agent for the Galactic Empire.

Biography
During the time of the Galactic Civil War, U-3PO was reprogrammed by Imperial agents to serve the New Order as an espionage droid, making the droid an unwitting spy for the Empire. U-3PO was inserted into the Tantive IV droid pool during the subjugation of Ralltiir. U-3PO later transmitted an S-thread signal to the Empire, allowing the Star Destroyer Devastator to track down the Tantive IV, thus allowing it to be attacked by the Devastator and boarded by Darth Vader and the 501st Legion.

Behind the scenes
U-3PO first appeared in Star Wars: Episode IV A New Hope (initially known just as "Star Wars") as a background character in the opening scene aboard the Tantive IV. However, it was not actually identified by name until the 1995 Star Wars Customizable Card Game by Decipher Inc. It was also stated to have been a double agent for the Galactic Empire in the flavor text for gameplay dynamics, although U-3PO's stance as such was indirectly implied earlier in the Star Wars Radio Drama, where it mentioned the possibility that the Tantive IV had been pursued by the Imperial forces due to a double agent onboard.

Appearances

 * Star Wars: Episode IV A New Hope
 * Star Wars Radio Drama
 * Tag & Bink Are Dead