Vetter Piin was a revolutionary Rov of an alien species from Ventooine. Han Solo assisted him in his efforts to depose the ruling Satab from the planet.
Piin was collaborating with a young man named Phalaf to assassinate Chrysalla, the wife of the reigning Satab, when Han Solo first arrived on Ventooine. Despite his aversion to violence, Piin believed that removing the Satabs was a necessary action. Phalaf launched an explosive at Chrysalla and her royal procession as they traveled through the city. Solo's intervention resulted in the bomb's destruction, causing the plan to fail. Piin narrowly escaped the Satab's guards, but Phalaf was apprehended. After witnessing Solo's attempts to protect a member of the ruling family, Piin considered the outsider a threat and ordered his assassination.
However, Piin reconsidered his assessment after Solo risked his own life to rescue local workers from a Cavern Monster in a subsequent event. Piin also learned that Solo was being considered as the next Satab to rule Ventooine. To determine Solo's true allegiances, Piin and another priest secretly entered the royal palace and saw the Satab trying to give Solo the shadeshine, the source of his power. The Satab detected Piin's presence, and the royal guard quickly captured the two priests.
Chrysalla's unexpected intervention allowed the priests to subdue their captors and flee. Upon their release, the priests discovered that Solo and Chrysalla had collaborated to kill the Satab, liberating Ventooine from their control. Piin congratulated the victorious pair before overseeing Chrysalla's eventual entry into the Hall of Satabs. After Solo left Ventooine, Piin assisted in building a shrine to Solo at his church. The large statue also held a memory stone that detailed Solo's role in overthrowing the Satabs.
Piin continued to maintain the shrine and perform his church duties during the Galactic Civil War. Lando Calrissian and Luke Skywalker, Rebel heroes, stumbled upon the shrine while being pursued by stormtroopers. Skywalker and Calrissian, surprised by the tribute to their friend, questioned Piin, who used the memory stone to recount Solo's story. After hearing the story, Piin assisted the Rebels in trapping the pursuing stormtroopers in the nullification chamber of the Hall of Satabs.