Adan Kraspen was an officer of the Rebel Alliance and New Republic who had formerly been an Imperial heavy trooper. Born on Corellia, Kraspen initially wanted to become a pilot in the Imperial Navy, but did not pass the medical examination and instead was sent to the Stormtrooper Corps due to his large build. The big man ended up becoming a lieutenant by the time of the Battle of Yavin, during which he was stationed on the Death Star. Kraspen and some other troopers attempted to escape from the battlestation on a transport, but were shot down by a Rebel patrol over Yavin and captured.
Already having resentment for the Galactic Empire for not letting him become a pilot, Kraspen became completely disillusioned following the destruction of Alderaan and defected. The former heavy trooper was sent to the Seventieth Reinforced Infantry, nicknamed the "Rose Regiment," a unit consisting of Imperial defectors. Kraspen served as the regiment's second-in-command after Jorund Varos, with whom he became good friends. He fought for the Rebel Alliance during the rest of the Galactic Civil War and helped establish the Rose Regiment's reputation for being skilled fighters. Kraspen was promoted to major shortly after the Battle of Endor.