R2-Z1 was a R2-series astromech droid. He was owned by Tereb Ab'Lon and was often used to store Imperial secrets that the Bothan had discovered. He escaped Bothawui with Ab'Lon but was unable to repair the Ambassador-class shuttle after it was damaged in a battle with TIE fighters. The shuttle came out of hyperspace and crashed near the Pit of Carkoon on Tatooine. The crash injured Ab'Lon and damaged R2-Z1. The droid was captured by Nim Bola who planned to sell him to the highest bidder.
He had a design flaw that caused him to unconsciously make a noise that sounded like "fweep". He was stubborn and single-minded, which made him very loyal to his master.
- The Complete Star Wars Encyclopedia
- The Essential Reader's Companion