Trey Callum, a male human, held the rank of sergeant major within the Rebel Alliance during the Battle of Hoth. Previously, he served as an Imperial officer before defecting to the Alliance. In 3 ABY, he was stationed at Echo Base on the planet Hoth. During the Galactic Empire's invasion of Hoth, Callum, who oversaw Outpost Beta, reported the presence of Imperial All Terrain Armored Transports.
As the Imperial forces clashed with the rebel defenders, Callum instructed his soldiers to concentrate their fire on the walkers. When Imperial snowtroopers entered the fray, the sergeant major commanded his troops to maintain their position, resulting in heavy losses for the snowtrooper force before the rebels began their withdrawal.
Before joining the Alliance to Restore the Republic to fight against the Galactic Empire, Trey Callum, a male human, was an Imperial officer. By 3 ABY, Callum had become an officer in the Alliance Military and found himself stationed at Echo Base on the planet Hoth. In this role, he commanded the soldiers assigned to Outpost Beta, a network of artillery emplacements situated between Hoth's Nev Ice Flow and South Ridge.
When the Empire discovered and attacked Echo Base, the base's shield forced them to use ground forces. Blizzard Force, a contingent of All Terrain Armored Transports tasked with destroying the deflector shield generator at Echo Base, was part of this deployment. As his troops readied their defenses, Callum used macrobinoculars from Echo Station 3-T-8 to spot the approaching walkers and reported their arrival to Echo Base. During the subsequent battle, Callum ordered his troopers at Outpost Beta to concentrate their fire on the enemy walkers, whose armor proved impervious to their attacks. Later, he instructed soldiers Emon Kref and Andry Ked to seek cover.
After the first AT-AT was destroyed, the soldiers celebrated. Around that time, Callum was informed by scouts that snowtroopers were closing in on his location. As the cheering subsided, the sergeant major walked along the trenches, informing the other rebels of the approaching Imperial troops and giving the order to hold the line against the Imperial forces. Callum's troops inflicted heavy casualties on the snowtroopers of Blizzard Force using anti-personnel batteries, but they were soon forced to retreat completely. Despite the Alliance's successful evacuation of a significant portion of its personnel, the Empire ultimately triumphed on Hoth by destroying the shield generator. It was reported that Outpost Beta was the first defensive position to fall.
While stationed on Hoth, Callum wore rebel snow gear, which included a white thermal flak jacket, white command gauntlets, a white insulated watch cap with a comm set, a white face wrap, white cap warmers, and anti-glare goggles.
Trey Callum was a character created for the 1980 original trilogy film, Star Wars: Episode V The Empire Strikes Back, where he was played by Bob Anderson in an uncredited role. Anderson, a stuntman, also served as the fight double for Darth Vader during his lightsaber duels in both The Empire Strikes Back and Star Wars: Episode VI Return of the Jedi. His full name was revealed on his card in the 2013 digital card game Star Wars: Force Collection.