Kana Sohma is a peripheral yet emotionally significant member of the Sohma family, though she is not part of the zodiac curse. She is a young woman with a petite frame, fair skin, and light brown eyes that match her short, light brown hair, which she typically wears in a bobbed style that reaches her chin. Two years before the main events of the series, Kana was introduced as Hatori Sohma's assistant, a role in which she quickly proved herself to be caring, friendly, and supportive. Her personality was notably cheerful and positive, drawing a direct comparison from Hatori himself to the series' protagonist, Tohru Honda, in terms of her overall attitude. She also aspired to become a doctor, demonstrating her ambition and dedication.

Kana's defining trait is her remarkable capacity for acceptance and her ability to find beauty in simple things. This is best exemplified by a question she once posed to Hatori, asking what snow turns into when it melts. When he gave the literal answer of water, she corrected him with the poetic and optimistic response that it turns into spring. This profound, hopeful outlook is what allowed her to accept Hatori unconditionally after she accidentally witnessed him transform into his zodiac form, the sea horse, due to the curse. She did not reject him; instead, she promised to stay by his side, and they quickly fell in love, beginning a two-month relationship that Hatori would later describe as being worth a hundred years of happiness.

The central tragedy of Kana's life stems from her relationship with the head of the Sohma family, Akito. When Hatori asked for permission to marry Kana, an enraged Akito violently attacked and injured Hatori, permanently damaging his left eye. Akito then manipulated Kana, blaming her for the injury and convincing her that her desire to marry Hatori was a mistake she should never have made since she was incapable of breaking the family curse. This psychological assault, combined with the trauma of witnessing Hatori's injury, plunged Kana into a deep, consuming guilt and severe depression, eventually leaving her unable to lead a normal life.

Witnessing her deterioration and wishing to save her, Hatori made the agonizing decision to use his own ability to erase all of her memories of their time together as a couple. Before the erasure, Kana tearfully apologized to Hatori for not being able to protect him. After losing her memories, Kana left the Sohma estate to continue pursuing her medical career. Her best friend from college, Mayuko Shiraki, was a constant source of support throughout these events, and the two remained close. Later in the series, it is revealed that Kana is engaged to a man unrelated to the Sohma family. Spotted in town by Hatori, she happily describes her love for her new fiancé, though she mentions feeling awkward around Hatori because she believes she had an unrequited crush on him in the past. Upon seeing her genuine happiness, Hatori is able to find peace and silently wishes her well. She eventually marries her fiancé, with Mayuko attending the wedding; Hatori chooses not to go, fearing his presence might trigger painful memories.

Kana does not possess any supernatural abilities. Instead, her impact on the story comes from her emotional strength and her unwavering acceptance of Hatori, despite his curse. However, her sensitivity also proved to be a vulnerability when turned against her by Akito's cruelty. Her primary role is to serve as a poignant figure from Hatori's past, representing a love that was destroyed by the oppressive nature of the Sohma family's curse and Akito's possessiveness. Through this experience, Kana transitions from a hopeful young woman in love to a deeply traumatized individual, ultimately finding a new, peaceful happiness outside the Sohma family's shadow, with the memories of her first great love forever lost.