Hisae Kamayai is a friend of Sana, Aya, and Mami in class 6, and continues to be one of Sana's friends in middle school. Though not as close as Aya and Fuka, she is usually seen with Sana is is both a large fan and close friend. She becomes angry when Sana can't come to her birthday because of her work, and feels she puts work ahead of everything else. They eventually come to an understanding and make up.
She is one of the more competitive girls in class 6, and seems to be the ringleader of sorts for the girls against the boys, though Sana tends to hold more sway than she. In this sense, she can be seen as the exact counterpart to Gomi. When they are both in middle school, she and Gomi become friends as the gender divide becomes less important to them.