The Penumbra Squadron was a fighter squadron in the 82nd Airborne Division of the Templars of Twilight Marine Corps. The Penumbra Squadron were an elite fighter force, akin to the New Republic's Rogue Squadron though specializing in atmospheric combat. When they were originally founded in 10 BBY they used various starfighters purchased from external sources. Following 8 ABY they, along with majority of the other starfighter squadrons in the Military adopted the Aeternus-class Heavy Interceptor.
They continued to use the fighter until 40 ABY when they were temporarily relocated to Anothelis, while at Anothelis they trained in the Itano Strike Fighter which they used during atmospheric and orbital missions. Following the Avengeance Incident they were transfered to Remsi Prime to train starfighter pilots in the new Strike Fighter. From 95 ABY and beyond they used the Vindicator-class Stealth Interceptor and the Itano depending on the mission.