Wilmon was a Ferrixian salyard worker who didn’t say much, but noticed a lot. Bix Caleen occasionally came to his father’s business, the Repaak Salyard, to use a hidden communication node to get in touch with a mysterious buyer. Wilmon was in on the secret.

When Pre-Mor security forces arrived on Ferrix to capture Cassian Andor, Wilmon and Salman were among the first to raise the alarm. They struck metal against metal to warn the town that danger was near. After the Pre-Mor soldiers began to use force, the Paaks freed Bix from their restraints and got her to safety. 

Weeks later, the Empire took an interest in the planet and established a base in a local hotel. The Imperial Security Bureau tracked a communication signal to the Paaks’ salvage yard and arrested Wilmon’s father. Salman was interrogated and killed. As he mourned, Wilmon used salvaged parts and his technical know-how to build an incendiary device. The town reached its tipping point during the funeral ceremony for Maarva Andor. Wilmon, stirred into action by his grief and her last words, threw the device at the Imperial forces and set off a series of explosions. Brasso helped him escape in the chaos and they ran to a transport in Zorby's Western Shiplot. Wilmon fled the planet along with Bix, Brasso, B2EMO, and Jezzi.

Along with Bix Caleen, Brasso, and Cassian Andor, Wilmon settled on the farming planet Mina-Rau, where they worked as agricultural mechanics until they were driven off the planet by Imperial inspectors.

Wilmon later went to Saw Gerrera’s partisan base on D’Qar to teach one of his men how to safely extract the unstable starship fuel rhydonium. After the soldier Wilmon taught was discovered to be a traitor, Wilmon joined Saw on their mission — where he learned to embrace the insanity of revolution.

Eventually, Wilmon went to the rebel base on Yavin 4, despite being more aligned with Luthen Rael than the growing rebel army. He convinced Cassian to return with him to Ghorman on a mission from Luthen Rael to assassinate Dedra Meero. During the ensuing chaos on Ghorman, Wilmon fought back against the Imperial attack. He chose to stay on the planet with Ghorman Front soldier Dreena, who he found broadcasting the events of the day to the galaxy.

After his getaway from Ghorman and Mon Mothma’s escape from the Imperial Senate, Wilmon returned again to Yavin 4, this time injured, alongside Cassian and Dreena. After hearing an emergency message he believed was from Luthen, Wilmon brought the urgent news to Cassian, who flew to Coruscant in an attempt to extract him.