Arr-Nine-Nineteen, despite professing to be a Jedi hunter droid, actually functioned as a spy for the Hutt Clan. During the Imperial Era, he was recruited by Gwi, the leader of the Hidden Hand crime syndicate, along with others, to form a team with the objective of hunting down the Sith Lord Darth Vader. However, when the cyborg bounty hunter Beilert Valance joined the group, he destroyed Arr-Nine-Nineteen, thereby exposing the droid's true allegiance to the rest of the team.
Arr-Nine-Nineteen was constructed with a spying mechanism embedded within him and tasked by the Hutt Clan to conduct espionage activities against the Hidden Hand criminal organization. He eventually cultivated a reputation as a Jedi hunter and was subsequently employed by Gwi, who headed the Hidden Hand, to become part of a team of bounty hunters assembled to hunt down and kill the Sith Lord Darth Vader.
When Beilert Valance, a cyborg, was being recruited in 1 BBY, Gwi characterized the droid as a "Jedi hunter who never retired." Upon encountering Valance, Arr-Nine-Nineteen sustained burns from the cyborg's palm blaster. Despite Gwi's insistence on the droid's necessity to the team, Valance revealed that Arr-Nine-Nineteen was in fact a mole working for the Hutts, asserting that his background as a Jedi killer was fabricated. Valance then extracted the spying device from the droid's interior and crushed it. Following Arr-Nine-Nineteen's demise, Valance and his team proceeded with their mission.
Arr-Nine-Nineteen was a droid programmed with masculine characteristics, possessing four arms and plating colored in a combination of blue, white, brown, and red, along with red photoreceptors.
Arr-Nine-Nineteen made his debut appearance in the first issue of the 2019 Star Wars: Target Vader comic-book series, penned by Robbie Thompson, with illustrations by Marc Laming and Cris Bolson, and published by Marvel Comics on July 3, 2019. Prior to the comic's official launch, the character received an indirect introduction through a mention of Valance's team by assistant editor Tom Groneman during a panel presentation at Star Wars Celebration Chicago in April 2019. This information was subsequently detailed in a StarWars.com article released on April 15.