Lin-D was an entertainment droid of the masculine-programmed variety, built for the purpose of delivering jokes and witty remarks. Constructed with a humanoid shape and covered in gray, silver, and orange plating, Lin-D's face was permanently fixed with a grin, and he possessed a pair of adjustable, white photoreceptors. These features highlighted his lighthearted attitude and his habit of finding humor in every situation. Some found Lin-D's talkative nature to be excessive; the protocol droid C-3PO considered him to be quite irritating.
Lin-D encountered C-3PO along with his Human companions, Mungo Baobab and Auren Yomm, in 15 BBY. This occurred after he was forced to join a team of enslaved rowers on the large galley known as the Roon Clipper, which was operated by agents working for Governor Koong of the Tawntoom Province on the planet Roon. When the astromech droid R2-D2 infiltrated the galley while exploring the Roon Sea, Lin-D was liberated along with the other slaves and escaped via a lifeboat. During the subsequent skirmish with Koong's drones, he was disabled, but R2-D2 repaired him, restoring him to his fully functional state.
Prior to the conclusion of 15 BBY, Lin-D, an entertainment droid, was built and programmed to bring joy and laughter. By the end of that year, Koong, the Governor ruling over the Tawntoom Province of the planet Roon, took possession of Lin-D. The droid was then forced by Koong to join a crew of organic and mechanical slaves aboard the ocean-faring galley called the Roon Clipper, where they were made to serve as rowers. Lin-D found himself chained to a rowing bench, forced to row the ship across the Roon Sea to Koong Island, carrying a cargo of precious gems known as Roonstones in the ship's hold. Shackled at the ankle to Lin-D during this journey was another mechanical being, a protocol droid named C-3PO, who had recently become a slave after being captured along with his master, Mungo Baobab, and their friend, Auren Yomm.
Lin-D attempted to improve the atmosphere by making jokes about their predicament, but C-3PO found him to be an annoyance. A crack of the enslaver's electro-whip prompted Lin-D to join the other captives in their hours-long rowing. Midway through the voyage, R2-D2, an astromech droid and colleague of C-3PO, who had secretly boarded the Clipper, freed Lin-D and the other prisoners from their chains. The freed captives then stole lifeboats from the vessel, and Lin-D joined C-3PO, R2-D2, Baobab, and Yomm in one of the boats as they made their escape. The escapees then encountered a violent storm and whirlpool, followed by an attack by drones that resulted in the loss of the lifeboat's motor and sail. During the attack, Lin-D was incapacitated when the sail fell on top of him.
After C-3PO and the others escaped the dangers of the sea, they checked on the unconscious entertainment droid. Fearing that Lin-D was beyond repair, they comforted R2-D2, who had grown fond of the comedic mechanical. However, during the remainder of their journey to Umboo Province, R2-D2 managed to restore Lin-D to full functionality. The revived droid expressed his gratitude and suggested that he, R2-D2, and C-3PO should form a traveling act called "Lin-D and His Cosmic Cutups."
Lin-D, being a class three droid, was specifically designed for direct interaction with organic beings. As an entertainment droid, his programming focused on spreading joy and humor. Consequently, he was constantly telling jokes, even in the most desperate situations. In fact, he argued that perilous situations were the best times to tell jokes, as humor was most needed during crises to lighten the mood. The droid often laughed at his own jokes, producing a high-pitched, staccato laugh that ended with a snort. While some listeners found his constant joking to be irritating, the droid had little sympathy for them. For example, when C-3PO expressed annoyance at his antics, Lin-D suggested that the protocol droid needed to relax. Lin-D was fluent in Basic and possessed a masculine programmed personality.
Lin-D's body was humanoid in structure, featuring two arms, two legs, a torso, and a head. His neck and limbs were long and slender, making him slightly taller than 1.7 meters, but he also had a noticeable pot belly. Lin-D's face was elongated, with a large nose and a long jaw positioned between wide cheeks. He had a large, perpetually grinning mouth that could open and close. Lin-D's neck, hands, nose, and brow were gray, while his fingers, mouth, jowls, forehead, and upper arms were silver. In contrast, his forearms, elbows, torso, and legs were a vibrant orange with light-orange accents. He had two orange circles where a Human's ears would be, and he had white photoreceptors with small black pupils. Lin-D could move the pupils independently or together, using this ability to enhance the comedic effect of his performances.
Lin-D appears in "Across the Roon Sea," an episode of the Star Wars: Droids: The Adventures of R2-D2 and C-3PO animated series. The episode was written by Sharman DiVono based on a story by Ben Burtt and directed by Ken Stephenson. It was originally broadcast on November 23, 1985. An animation error results in Lin-D having five fingers on each hand in some scenes, but only four in others.