Since middle school, Futaba has always believed that boys were too rough and violent. Tanaka Kou was the only exception, and Futaba wanted to know him better. The two share brief, sentimental memories—including a plan to go to the summer festival together. After accidentally telling Naitou, Kou's friend, that she hates all boys within Kou's hearing proximity, she worries about his opinion of her but convinces herself that he understands he is an exception. The summer festival arrives, and Kou doesn't show up. Returning from the summer vacation, Futaba hears that Kou transferred to another school without explanation. Futaba realizes how much she liked Kou and regrets not telling him how she felt.
In high school, Futaba's character is drastically different. No longer feminine or cute, she makes herself as unattractive as possible. Futaba was an outcast in middle school because the girls were jealous of her popularity with boys. Determined to have friends in high school, she sacrifices her true, girly self for her classmates' approval. Although Futaba is strong-willed, stubborn, and passionate, she prefers to be accepted for who she isn't than ostracized for who she is. Futaba eventually falls in love with Kou again. However, she constantly worries that he has no feelings for her and believes he only sees her as a past crush. She is dating Touma.
Futaba is portrayed by Tsubasa Honda in the live action movie adaptation.