Brenna held the rank of colonel and was a female human who commanded a brigade within the Galactic Empire's military. She held the strong belief that her brigade surpassed the capabilities of those stationed aboard the Death Star.
Throughout the duration of the Galactic Civil War, Brenna and the soldiers under her command were involved in numerous conflicts against the Rebel Alliance, frequently clashing with Major Shin and his rebel forces.
Not long after the Battle of Yavin concluded, as the Rebels were in the process of evacuating their base located on Yavin 4, Brenna and her soldiers made planetfall and initiated an attack on the base, with the intention of seizing data drives containing sensitive Rebellion information.
On Tatooine, Imperial forces obtained intelligence regarding an elite Rebel cell operating from within Mos Eisley. Brenna spearheaded an assault on the city with her troops, aiming to prevent a Rebel U-wing from successfully taking off during an evacuation. In contrast to the Rebel commander, Brenna displayed no concern for civilian casualties, informing her troops that they were deemed "acceptable."
While stationed at the Shipyards in orbit around the planet Fondor, Brenna was compelled to command Imperial fighter pilots when Rebel ships launched an attack, seeking to destroy an Imperial II-class Star Destroyer undergoing repairs while docked.
Upon the Empire's discovery of the Rebellion's secret base situated on the remote planet of Hoth, they initiated a comprehensive assault with the objective of permanently eliminating the Rebels. During the battle, General Maximilian Veers successfully destroyed the base's power generator, thereby enabling Imperial ground forces to land. As the Rebels desperately attempted to evacuate whatever they could, Brenna and her troops launched attacks on the base's east and west hangars, endeavoring to sever the fuel lines to prevent the Rebel ships from achieving liftoff.
Later, during the Battle of Endor, Brenna held a position at Command Center North on the incomplete second Death Star. During the conflict, a Rebel CR90 corvette collided with one of the Battle station's hangars. The surviving Rebel passengers engaged Brenna's troops in a skirmish with the main objective being to sabotage the station and escape.
Following the destruction of the Death Star II, Brenna was in command of a lone Imperial II-class Star Destroyer accompanied by several Imperial fighter craft, launching an assault against an MC80 Star Cruiser. The battle unfolded amidst the wreckage of the destroyed Death Star.
On the moon of Endor, Brenna was present at Research Station 9 during its evacuation. The station, along with a nearby outpost, was attacked by Rebel forces attempting to commandeer an All Terrain Armored Transport for use in their assault. Brenna and her troops mobilized to defend the base.