Kisa Sohma is a young girl who is a member of the Sohma family, cursed by the spirit of the tiger in the Chinese Zodiac. As a result of this curse, she transforms into a small golden tiger cub when embraced by a member of the opposite sex or when her body is under significant physical or emotional stress. She is one of the youngest members of the cursed zodiac, and is a freshman in junior high school.

Kisa is a gentle and extremely shy child, widely considered the most timid of all the cursed Sohmas. Her naturally striking appearance, which includes unique golden-yellow hair and golden eyes, is a direct effect of the curse and became the source of relentless bullying when she started seventh grade. Her classmates first mocked her looks, and when that failed to break her spirit, they resorted to ignoring her completely, only paying attention to laugh at anything she would say. This cruel ostracization deeply wounded her, leading her to internalize her shame. Rather than burden her worried mother with the problem, Kisa stopped speaking altogether and eventually ran away from home.

Her motivation throughout the story is rooted in a deep desire for acceptance and to overcome her overwhelming feelings of worthlessness and insecurity. After running away, she is found by the ox of the zodiac, Hatsuharu Sohma, who brings her to the home of Shigure Sohma. It is there she meets Tohru Honda. Initially defensive, Kisa bites Tohru’s hand, but Tohru’s response is not one of anger. Instead, Tohru openly shares her own childhood experiences with bullying, creating a powerful empathetic connection that becomes the turning point for Kisa. Seeing Tohru as a big sister, Kisa attaches herself to Tohru and, through her kindness and understanding, begins the slow process of healing. With further encouragement from Yuki Sohma, who relates to her pain after a silent period in his own past, Kisa finds the courage to speak again and, eventually, to return to school and face her problems directly.

Kisa's key relationships are central to her development. Her bond with Tohru Honda is the most significant, representing a source of unconditional love and stability. She also shares a close, brother-sister-like relationship with Hatsuharu Sohma, who cares for her deeply and was the one who found her after she ran away. Yuki Sohma also shares a special connection with her, understanding her past muteness due to his own experiences with the family head, Akito. Her most complex relationship is with Hiro Sohma, the sheep of the zodiac, who is only a year older than her. They have been close since childhood, and Hiro secretly loves her. However, when he confessed this to Akito, the family head brutally attacked Kisa, hospitalizing her for two weeks. Out of guilt and a desperate wish to protect her from further harm, Hiro distanced himself from her, a withdrawal that added to her feelings of isolation. Kisa, unaware of the reason for his coldness, is confused but never stops believing in him.

Over the course of the series, Kisa shows remarkable emotional growth. She evolves from a completely mute, withdrawn girl who ran away from her problems into someone who can proudly state that she was able to greet another person properly. She decides to return to a school environment that had rejected her, demonstrating a newfound strength and resolve. In the end, she is one of the zodiac members whose curse is finally broken, freeing her from the cycle of transformation and the control of Akito, allowing her to look toward a future without the burden of the spirit of the tiger.