Sora Naegino is the protagonist of the anime series Kaleido Star. As a young child, her parents took her to see the Kaleido Stage, a world-famous circus that left a lasting impression on her. Shortly after that visit, her parents died, and Sora went to live with her aunt and uncle. Despite this personal tragedy, the memory of the Kaleido Stage inspired her to pursue a career as a performer, and upon reaching adulthood, she traveled from Japan to Cape Mery, California, with her aunt and uncle's hesitant approval, to audition for the company. Upon arrival, she encountered a series of misfortunes: she got lost, had her bag stolen, and consequently missed the official audition. However, after a chance incident where she displayed her natural agility, the owner of the Kaleido Stage, Kalos, offered her a place in the actual show. Most of the cast initially did not accept her due to the unusual circumstances of her joining, but Sora gradually won them over through persistent hard work, dedication, and her naturally magnetic and earnest personality.

Sora is characterized by her unwavering optimism, determination, and resilience. Even when faced with adversity, she refuses to give up and approaches every challenge with enthusiasm and a strong work ethic. Her primary motivation is her love for performance and her dream of becoming a true star on the Kaleido Stage, a dream rooted in her childhood memory of the place and her desire for connection. She is also notably empathetic and caring, often putting the needs of others before her own and finding deep fulfillment in helping her colleagues succeed. Throughout the series, Sora undergoes significant development. She initially struggles to earn respect and master difficult routines, but through sheer persistence and the guidance of mentors, she gradually hones her skills. In the first season, she learns to perform complex acrobatic moves and, after forming a deep partnership with the star performer Layla Hamilton, successfully executes the Legendary Great Maneuver, a highly dangerous and demanding act that requires perfect synergy between two performers. In the second season, after Layla's departure, Sora continues to grow, taking on new challenges and rivals such as the talented newcomer Leon Oswald and the figure skater May Wong. Under the guidance of the magical stage spirit Fool, who only she can see, she realizes her potential to become not just a skilled performer, but a true star capable of inspiring others and elevating the stage itself.

Key relationships heavily influence Sora's journey. Her most significant relationship is with Layla Hamilton, initially a distant and stern idol who sees Sora as unworthy, but who eventually becomes her partner, mentor, and close friend after they share the Legendary Great Maneuver. She shares a unique bond with the mysterious spirit Fool, who guides her and reveals that she has been chosen by the stage. Ken Robbins, a fellow performer who also acts as a stagehand, provides her with constant encouragement, support, and practical help in her training. Her relationships with other cast members, such as Mia Guillem and Anna Heart, also grow from initial skepticism into genuine friendship and teamwork. Sora's notable abilities include her natural acrobatic talent and her potential to perform extraordinary stage maneuvers, particularly in aerial performances. Her true strength, however, lies in her ability to inspire and unite those around her, as well as her unique connection to the magical elements of the stage, which allows her to perform acts that transcend ordinary circus performance. By the end of her journey, she embodies the ideal of a Kaleido Star: a performer who not only dazzles the audience with skill but also touches their hearts with passion and determination.