Quarrie's Mon Calamari engineer was assisted by BG-81, an astromech droid, in the years before the Battle of Yavin and throughout the Galactic Civil War.
On the planet of Shantipole, BG-81 helped Quarrie, a Mon Calamari starship engineer, construct his Prototype B6. This prototype subsequently served as the foundation for the Rebel Alliance's B-Wing. When the Spectres consisting of Hera Syndulla, Sabine Wren, and Garazeb Orrelios arrived on Shantipole to evaluate the new starfighter, BG-81 was there.
When Hera piloted Prototype B-6 on a test run across Shantipole's canyons, the astromech droid was present. During the flight, Quarrie instructed BG-81 to equip the rebels' shuttle, the Phantom, with a hyperdrive and an astromech socket. Later, when Hera utilized the prototype starfighter to breach the Galactic Empire's blockade of Ibaar, the droid and Quarrie were aboard the Phantom. BG-81 and Quarrie departed the rebel fleet after the battle to oversee the production of additional B-Wings for the rebellion.
Eventually, BG-81 and Quarrie enlisted in the Rebel Alliance on the flagship Home One. While Quarrie and the Freemakers were busy building, the B1-series battle droid R0-GR regaled BG-81 with tales from the past, during which the latter droid spent much of that time in sleep mode.
Serving the Mon Calamari starship engineer Quarrie, BG-81 was a Lothal astromech droid. BG-81 assisted Quarrie in building the experimental Prototype B6 starfighter. BG-81 was on hand for both the starship's test flight and its initial operational deployment.
The Star Wars Rebels Season Two episode "Wings of the Master," which debuted on Disney XD on November 11, 2015, marked BG-81's debut. He has brief appearances in a number of LEGO Star Wars: The Freemaker Adventures Season Two episodes. BG-81 is still employed by Quarrie in the series, who is now employed by the Rebel Alliance aboard their flagship Home One. BG-81 later replays images of various starships, but none match Rowan Freemaker's Force vision of the Arrowhead. During Rowan's Quest to build the Arrowhead, BG-81 also helps Kordi Freemaker's effort to obtain an Imperial list of planets containing kyber crystals from an Imperial base. BG-81 later awakened Quarrie so Rowan could show him his "Ugly" starship.