She is the younger sister of Sawanoi Kou's mother, making her Kou's aunt and an extended relative of Kyouko's.

Hanae is extremely pleasant and likes having company. She is greatly entertained by Kyouko and her friends when they spend the summer in the family villa. Unlike her older sister, Hanae is very sociable. She is a little embarrassed that her sister says such harsh things about Kyouko's mother and their guests during a private conversation that Akira accidentally overhears.

She has two daughters who are friendly girls that appear to be around Kou's age. They spend a day teaching Pon-chan, Yassan and Mogi how to horseback ride while Hanae nurses Fumi and Akira back to health after they catch summer colds.