Alexsandr Kallus was a human male revolutionary who served as an agent of the Imperial Security Bureau, operating number ISB-021, before becoming a rebel spy in the formative days of the Alliance to Restore the Republic.
As an Imperial operative, Kallus was a firm believer in bringing order to the galaxy. He worked to suppress dissent on numerous worlds, fighting against the insurgency of Saw Gerrera on Onderon, participating in the genocide on Lasan, and leading the hunt for the rebels of the Ghost on Lothal. His efforts on Lothal were largely unsuccessful, leading to an escalation of force against the growing rebellion in the form of both Grand Moff Wilhuff Tarkin, Governor of the Outer Rim Territories, and the Sith Lord Darth Vader.
After pursuing the Ghost crew for over one year, Kallus attempted to trap them in orbit of Geonosis. In the ensuing conflict, Kallus and one of the Ghost crew members, the Lasat warrior Garazeb Orrelios, were trapped on the frozen moon Bahryn. They found kinship as soldiers as they worked together to survive, and Kallus learned more about the rebels and their camaraderie. It was enough to make him question his beliefs about the Empire and the rebellion, and he covertly became a rebel spy under the codename of Fulcrum, thanks to Zeb. He fed the rebellion information about the Empire’s activities, including those of Grand Admiral Thrawn, who was tasked with eliminating the rebels of the Lothal sector.
Thrawn discovered Kallus’ true allegiance after realizing there was a rebel spy in his midst, and Kallus was captured as he attempted to feed the rebels information for their planned attack on Lothal. Ultimately, Thrawn discovered the rebel base on Atollon and launched an attack that devastated the rebellion. Kallus broke free of Imperial custody during the battle and was taken in by the Ghost, and accompanied the surviving rebels to the base on Yavin 4, thus escaping from certain execution.
Becoming a full-fledged member of the Rebellion, Kallus assisted the Alliance both tactically and in the battlefield. As a key ally of the Ghost crew, he aided them in their successful liberation of Lothal. After the Empire’s demise in 4 ABY and the subsequent end of the Galactic Civil War in 5 ABY, Orrelios brought Kallus to Lira San, the ancient home of the Lasat people, to show the former ISB Agent that he had not destroyed the Lasat species after all. As a partner to Orrelios who turned against his former Empire, the Lasat welcomed Kallus as one of their own.