Winter Celchu, the only child of Sheltay Retrac, was raised as a sister and companion to Princess Leia Organa during the dark years of the reign of the Galactic Empire. Like her adopted sister, Winter became a pivotal player in the Galactic Civil War, serving in various roles, most notably as a spy. As an operative of Alliance Intelligence, she served the Rebel Alliance and later the New Republic. Her holographic and audiographic memory gave her a special advantage in piecing together confusing situations or even simply computing data. She was often attached to Rogue Squadron as an intelligence officer, though sometimes under false identities.
Winter also served a vital role as Leia Organa's best friend, aide and confidante. She had special relationships with Leia's children Jaina, Jacen, and Anakin Solo, whom she raised during their first years of life. She had a long romance with Tycho Celchu, from whom she was often separated by war, but the couple would eventually marry. She was also known to be a close personal friend of Admiral Ackbar.