Akari Kanzaki is the central protagonist of Battle Athletes, a young woman whose journey is defined by the immense weight of legacy and the struggle to find her own identity. She lives in a distant future where athletic competition has replaced warfare, and the highest honor a female athlete can achieve is the title of Cosmo Beauty. This title was once held by her mother, Tomoe Midoh, who is remembered as the most legendary Cosmo Beauty in history. It is this towering legacy that shapes Akari's life, as she carries the burden of being the daughter of an icon whose records and fame she feels incapable of living up to.

In terms of personality, Akari is initially presented as a clumsy, timid, and deeply insecure sixteen-year-old who lacks confidence in her own abilities. She is prone to crying and frequently expresses a desire to give up or hide from the pressures placed upon her, a trait that can be frustrating to those around her but is portrayed as a genuine flaw she must overcome. Her lack of self-belief is a central aspect of her character; she cannot see the natural talent she possesses, which is a direct inheritance from her mother. Despite her clumsiness and moments of hopelessness, Akari is fundamentally kind-hearted and possesses a never-say-die spirit that emerges when she is supported by her friends. Her motivations are rooted in a promise, often stated to have been made on her mother's deathbed, to attend the University Satellite and follow in Tomoe's footsteps, even though she never saw her mother compete.

Akari's role in the story is that of a classic underdog who must grow into her potential. The narrative follows her from her difficult first days at a training school in Antarctica to the competitive arena of the University Satellite in space. Her primary struggle is psychological rather than physical; the key to unlocking her extraordinary athletic gifts is not more training, but the cultivation of self-confidence and the will to win. Her development is a slow and often painful process of evolving from a whiny, co-dependent slacker into a fierce and confident competitor. A major turning point in her journey involves her quitting the school and retreating to her isolated family home, only to be brought back by the unwavering support of her best friend. This act forces her to confront her painful past and stop running from her destiny.

Her key relationships are the primary catalysts for this growth. Her most significant bond is with Ichino Yanagida, a rough-and-tumble friend who serves as her emotional rock and anchor. This relationship is portrayed with deep emotional intensity, with the narrative suggesting that Akari falls in love with Ichino over time, making their bond the dominant love story of the series. She also develops a crucial rivalry and friendship with the perfectionist Jessie Gurtland, whose initial hatred for Akari paradoxically spurs the heroine onward. At the University Satellite, she is teamed with Kris Christopher, who declares her love for Akari upon their first meeting, and the shy Anna Respighi, forming a team that must learn to function together. Through these connections, the other girls also learn valuable lessons from Akari's inherent kindness and unique perspective.

Regarding her abilities, Akari initially appears to be a hopeless athlete who is slow and fragile, often landing in last place. However, this is a deception caused by her own mental blocks. As she gains confidence, she begins to tap into a latent, world-class athleticism that is her birthright as Tomoe Midoh's daughter. Her natural talent is so profound that she can achieve remarkable feats, such as winning a triathlon without specific training, purely by unlocking her self-belief. Her development is marked by her ability to overcome psychological hurdles, each breakthrough allowing her to shave significant time off her running speed or perform beyond her previous limits, transforming her from a "doe-eyed lump" into a fierce competitor capable of contending for the Cosmo Beauty title.