By the time the year reached 5 BBY, the human Cassian Jeron Andor was deeply involved in a quest: to locate his sister, Kerri, from whom he had been separated since she was a mere six years old, back on their shared homeworld of Kenari. The young Andor, known then as "Kassa," had joined an expedition to investigate a downed Galactic Republic transpo corsair, an event that led to his separation from his peers. He was subsequently rescued from the planet by Maarva and Clem Andor, who sought to shield him from an approaching Republic force. This act led to his adoption into the Andor family and a new life on the planet Ferrix. Despite this new beginning, Cassian was haunted by the feeling that he had abandoned his sister, a feeling amplified by reports of a mining disaster that supposedly wiped out all life on Kenari during the Imperial Era.
Cassian scoured the galaxy in his relentless pursuit of Kerri. In the year 5 BBY, acting on information about a Kenari girl employed at the Leisure Zone brothel located on Morlana One, Cassian ventured there. However, a hostess informed him that the woman he sought had left months prior. This search also brought him into a deadly confrontation with Preox-Morlana security officers Kravas Drezzer and Verlo Skiff, both of whom met their end at his hands. This incident had far-reaching consequences, drawing Cassian into the orbit of the Galactic Empire and the early rebel movement. After the Aldhani heist, Maarva urged her adopted son to abandon his search for Kerri, assuring him that he bore no responsibility and suggesting that his sister had likely perished. Cassian, however, remained silent. Following Maarva's death from old age and the subsequent uprising on Ferrix, Cassian aligned himself with Luthen Rael's cell within the burgeoning rebellion.
Tony Gilroy explained that Kerri's disappearance is instrumental in establishing the recurring theme of Cassian Andor's experience of loss and abandonment, a theme that holds particular significance for season two.