S-R6

S-R6, also known as Essar, was an assassin droid active during the Galactic Civil War. For each of his missions, he had his central programming and circuits transferred to a different droid shell for the purposes of disguise. S-R6 developed an enthusiasm for firearms, which affected his personality traits, and came to own a private collection of guns from throughout the galaxy. He also employed a protocol droid, T-3PO, as a valet and go-between.

At some point, an underground droid enclave on the planet Trevura hired S-R6 to assassinate Trevura's Imperial governor, Merno Blask. In response, the governor arranged for Imperial stormtroopers to field-test experimental anti-droid blaster rifles in the streets of Voma, a city on Trevura. A group of Rebel Alliance agents also present in Voma eventually fought and killed two of the stormtroopers carrying the inhibitor guns. Shortly after the firefight, the Rebels came into contact with S-R6, who was masquerading as an ASP-series labor droid at the time. When the group visited the garage the assassin droid was using as a hideout, S-R6 expressed his eager interest in the dead troopers' inhibitor guns. The garage was then attacked by another group of stormtroopers, and after S-R6, T-3PO, and the Rebels defeated the Imperials, the assassin droid escaped his hideout with the pair of the inhibitor guns.

Text and facts from the “S-R6” article on Wookieepedia, licensed under CC BY-SA 3.0. Modified for this site.