The initial assignment for Brenn Tantor following his defection to the Rebel Alliance was the Mission to Ruul.
As an act to prove his loyalty after switching sides, Tantor offered the Alliance an All Terrain Armored Transport. However, this required the assistance of Beri Tulon, Tantor's former instructor, who had spent many years assigned to an AT-AT factory. The problem was that Tulon had been apprehended by the Galactic Empire during a failed defection attempt orchestrated by Tantor and subsequently imprisoned at the Tarkin Detention Facility located on Ruul.
General Tyr Taskeen closely oversaw Tantor as he led a small strike force to Ruul, where they planned to ambush the convoy transporting Tulon to the detention center. However, before Tulon's convoy arrived, another smaller convoy passed by, carrying a captured leader of the Ruulian Rebels. Tantor quickly dispatched the guards and returned the leader to his people who were nearby.
Beri Tulon is escorted to Tarkin Detention Facility.
Shortly after, Tulon's convoy appeared. Tantor's troops ambushed from the high ground, taking down the stormtroopers and walkers guarding him. Tulon was swiftly placed aboard a transport, and the group hurried to the designated extraction point, encountering Imperial patrols and defenses en route.
Once they were safe, Tantor inquired about the location of the factory from Tulon. Tulon revealed that it was situated on the asteroid Trasse, but access required specific codes. Fortunately, the necessary codes could be found at the nearby Imperial computer bank located at Sounder Flats.
Still relying solely on infantry and transports, reinforced by the Ruulian Rebels and four of their captured walkers, Tantor successfully overwhelmed the Imperial bases protecting the complex and executed a successful data raid, despite facing significant Imperial counterattacks. After Beri Tulon extracted the codes from the facility, Tantor and his forces withdrew as rapidly as they had arrived.