Vetter Piin was a revolutionary and Rov of an unidentified species from Ventooine (a non-Human species), who received assistance from Han Solo in his efforts to depose the Satab who governed the planet.
Piin was collaborating with a young man named Phalaf to assassinate Chrysalla, the wife of the reigning Satab, when Han Solo initially arrived on Ventooine. Despite Piin's aversion to violence, he recognized the necessity of taking action to liberate Ventooine from the Satabs. Phalaf launched an explosive toward Chrysalla and her royal procession as they traveled through the city. The plan, however, failed because Solo intervened and destroyed the bomb. Piin narrowly avoided capture by the Satab's guards, but Phalaf was apprehended. After observing Solo's attempts to rescue a member of the ruling family, Piin deemed the outsider a threat and ordered his assassination. However, Piin reconsidered his judgment after Solo risked his own life in a subsequent incident to save several local workers from a Cavern Monster. Furthermore, the Rov learned that Solo was designated to become the next Satab of Ventooine. Piin and another priest secretly entered the royal palace to ascertain Solo's true allegiance, where they witnessed the Satab trying to bestow the shadeshine, the source of his power, upon Solo. Unfortunately for the undercover priests, the Satab detected Piin's presence, and the royal guard promptly captured them.
Chrysalla's unexpected intervention enabled the priests to subdue their guards and escape. Upon gaining their freedom, the priests discovered that Solo and Chrysalla had collaborated to kill the Satab, thus liberating Ventooine from their rule. Piin offered his congratulations to the victorious pair and then oversaw Chrysalla's eventual entrance into the Hall of Satabs. After Solo's departure from Ventooine, Piin contributed to the construction of a shrine dedicated to Solo at his church. The sizable statue also incorporated a memory stone that chronicled Solo's role in overthrowing the Satabs.
During the peak of the Galactic Civil War, Piin continued to maintain the shrine and perform his duties at the local church. Luke Skywalker and Lando Calrissian, Rebel heroes, stumbled upon the shrine while being pursued by stormtroopers. Surprised by the tribute to their comrade, Skywalker and Calrissian questioned Piin, who then played Solo's story through the memory stone. After listening to the narrative, Piin assisted the Rebels in trapping the pursuing stormtroopers within the nullification chamber of the Hall of Satabs.