During the Clone Wars, Osia was among a group of Believers who traveled to a secret Metatheran Cartel base on the moon Tilnes, where they released a virus that was fatal to Caarites. However, an electromagnetic pulse caused the base to shut down, trapping the Believers inside. They encountered Ko Bas, Caarite who had been mutated by the virus and after he attacked them, only Osia and Aris, another Believer, were able to escape. They took refuge in the facility's security office, where they found two other mutated Caarites. The two Believers used the Force to control the minds of the Caarites and attempted to bypass the base's security system, so they could escape. A short time later, the heroes of Cularin entered the base and the two Believers attacked them, to prevent the heroes from learning about the virus. However, Osia and Aris were defeated.