- "He’s just a robot with a simple dream of killing all humans. That’s so wrong."
- — Bacta
R2-D20 was an astromech droid that worked with the Jedi Sian Jeisel from the time she was a Padawan learner until she was killed during Order 66. While the clone trooper Bacta was unable to protect Sian Jeisel due to his battle with his commander Synox, he and R2-D20 escaped together to Tatooine, where Bacta landed himself in an Imperial prison yard.
R2-D20 was in Chalmun's Cantina on Tatooine when Grizelle Jorun, Tryst Valentine, and Leenik Geelo first encountered Aava Arek on her hunt for the infant Tamlin. After initially being ratted out by Leenik to the stormtroopers in a desperate bid to save himself, D20 demonstrated his signature ruthlessness by immolating a stormtrooper and blowing several holes in the cantina, leading the bartender to ban all droids from the cantina from then on. He then told the others about Bacta, and eventually the crew was reunited and escaped from Tatooine.
Five years later R2-D20 was a member of The Mynock's crew when they boarded The Murder Ball in pursuit of Aava Arek and the kidnapped Tamlin. D20 provided valuable logistical support on the mission, orchestrating a massive jail break (leading to the death of MANY Bothans) and sabotaging Aava's TIE fighter, but he was electrocuted and rendered inoperative during their escape.
While The Mynock was in the possession of Lyntel'luroon on Myrkr, she wired him up to the ship's comm systems to jury rig a system to monitor Imperial communications and pull relevant messages out of the traffic for Lyn's perusal. He remained in this state until the crew arrived on Phindar, where he was taken from the ship in the crew's absence by the authorities when it was determined he was still registered to a phony address on Kamino used by the clone soldiers to smuggle contraband.