Admiral Jion Trynn was a member of the Imperial Navy throughout the duration of the Galactic Civil War. In the year 0 BBY, he commanded a task force consisting of two Imperial-class Star Destroyers, specifically the Adjudicator and the Relentless, and was dispatched to Gerrard V in order to suppress an uprising that had broken out there. A local rebel force had seized control of the capital city, Harazod; following the destruction of the planet's small rebel fleet in orbit, Trynn deployed ground forces to recapture the city.
Trynn endeavored to negotiate a settlement, presenting surrender conditions to the rebel commander, General Camon Udeon, but the offer was rejected. Consequently, the admiral withdrew his forces from the city and initiated an orbital bombardment targeting the urban core of Harazod. Trynn had a suspicion that the rebels were connected to Mon Mothma's Alliance to Restore the Republic; however, due to the lack of prisoners for questioning, he was unable to confirm this suspicion.