Zaster functioned as an officer within the Imperial Military throughout the Galactic Civil War era. Following the Battle of Yavin, Zaster achieved the position of General and oversaw the Imperial Second Division stationed on Tatooine. During his command, Zaster expressed considerable worry regarding the growing influence of the criminal organization referred to as the Alkhara Bandits. Ultimately, General Zaster dispatched a formal communication to all Imperial staff located on Tatooine, with the aim of augmenting patrol presence within the regions affected by the Bandits' operations.