Before the Great Sith War, Captain Finhead Stonebone, a well-known pirate, had a Zexx associate named Fnnbu. In 3999 BBY, Fnnbu went to the desolate planet Ambria at the behest of Bogga the Hutt, a local crime lord operating from the Stenness Node. He was part of a group that included enforcers working for Bogga and pirates associated with Stonebone. Their mission was to recover a lost shipment of valuable Adegan crystals from Jedi Master Thon, Bogga's sworn enemy. When they arrived on Ambria, they were surprised that Thon didn't resist. The crystals were quickly located. However, Nomi Sunrider, Thon's Jedi apprentice, attempted to turn the pirates and enforcers against each other by using a Force power called battle meditation. Her attempt succeeded, and Fnnbu was the first to be affected by the Force power. Fnnbu became enraged and attacked everyone, both friend and foe. Soon, all the pirates and enforcers were fighting each other. Sunrider then used her lightsaber to attack the group, killing Fnnbu, among others.
Leading up to the Great Sith War, Fnnbu was an ally of Captain Finhead Stonebone, the pirate. In 3999 BBY, Fnnbu joined a group made up of Stonebone's pirate gang members and enforcers who worked for Bogga the Hutt, a crime lord based on the Stenness Node. They were sent on a mission to the remote planet Ambria to retrieve a lost shipment of Adegan crystals from Jedi Master Thon, Bogga's sworn enemy. Bogga promised to free Stonebone's crew, who had been captured after a failed raid on an Ithullan ore hauler, in exchange for the crystals. The group landed near Master Thon's compound on Ambria and soon encountered Master Thon, who surprisingly refused to fight. One of Bogga's men quickly discovered the Adegan crystals, but refused to share them with the pirates. While Fnnbu and Stonebone argued with the enforcers about who deserved credit for finding the crystals, Nomi Sunrider, Thon's Jedi apprentice, used a Force power known as battle meditation in an attempt to turn the invading crew against each other by influencing their minds.
Nomi Sunrider's battle meditation first took hold of Fnnbu. Fnnbu stepped forward and demanded to handle the crystals, promising to guard them for Bogga the Hutt. When the enforcers refused, Fnnbu became violently angry, claiming the crystals were his and attacking both allies and enemies. A large brawl erupted between the enforcers and the pirates, eventually leading to infighting within each group. Fnnbu personally fought C'borp, a fellow pirate and the chief gunner on the pirate ship Marauder Starjacker. As the pirates and enforcers fought, Nomi Sunrider activated her lightsaber and attacked them. Fnnbu and the others were caught off guard, and the Jedi trainee quickly killed Fnnbu.
Fnnbu was a tough, imposing pirate in Finhead Stonebone's gang. He was easily swayed by mind-based Force powers, as he was the first to succumb to Nomi Sunrider's battle meditation. He often spoke of himself in the third person and respectfully referred to Finhead Stonebone as "cap'n." He possessed immense physical strength, easily overpowering several beings who tried to restrain him during the brawl on Ambria.
Fnnbu's first appearance was in Tales of the Jedi: The Saga of Nomi Sunrider, the second story arc of the Tales of the Jedi comic book series, written by Tom Veitch and released from early 1993 to late 1994. Fnnbu played a minor role in the third and final issue of the arc, where he was killed at the climax. David Roach illustrated Fnnbu in this appearance. Although Fnnbu was not included in the Tales of the Jedi audio adaptation, his lines were given to several unnamed characters. In 2008, The Complete Star Wars Encyclopedia included an entry for Fnnbu.