Plat Mallar, hailing from the Imperial colony world of Polneye within the Koornacht Cluster, was a Grannan. Serving in Polneye's defense forces, he piloted a variety of TIE fighters. He was the only child of Plat Hovath and Fall Topas.
During the Great Purge, when the Yevetha launched their attack, Plat Mallar distinguished himself by being the only being to slay a Yevetha during the entire conflict. He was also the lone survivor from Polneye, having bravely piloted his TIE Interceptor into the void of space in a desperate attempt to alert others. Days later, on the verge of death, New Republic forces discovered him. The "Plat Mallar tapes," recorded within his cockpit, later proved instrumental in swaying public sentiment within the New Republic, fostering support for retaliatory action against the Yevetha.
Ackbar took Plat Mallar under his protection. Leveraging his TIE piloting skills and the Admiral's influence, Mallar swiftly entered the New Republic's military, albeit initially as a ferry pilot. He participated in the mission that led to Commodore Han Solo's capture by the Duskhan League. While flying an X-wing starfighter that fell victim to an ion cannon assault, he relentlessly tried to reignite his fighter.
During the final battle against the Yevetha, Plat Mallar was stationed on the cruiser Mandjur. Piloting his shuttle, Mallar undertook three rescue missions to retrieve pilots, successfully recovering one alive and two deceased. Subsequently, Mallar boarded the X-wing of his commander, Captain Tegett (who was incapacitated), and joined the fray. He ultimately sacrificed his life by ramming a Yevethan vessel that was targeting the Mandjur. His ultimate sacrifice saved countless lives, just as his desperate flight from Polneye ensured neighboring worlds within Koornacht would not have to endure another Great Purge.
Upon his enlistment, Chief of State Leia Organa Solo formally admitted Polneye into the New Republic. As the sole survivor, Plat Mallar held the position of senator de facto and could have occupied the seat had he chosen to. However, he instead sought retribution against the Yevetha. Consequently, Organa Solo decided to keep Polneye's seat vacant as a lasting reminder of the Yevethan's atrocities.