Sanae is an underclassman to the rest of the club members. She, like Rikka, is a Chuunibyou. She claims that she is Rikka's servant and wants to take her master's place. Her "power" is Mjolnir, a pair of hair nunchucks. Despite being a Chuunibyou, she is top in her class. Little was known about her relatives but it's implied that she is from a rich family.

She eventually becomes the student council president with Nibutani as her vice president.
Her "nunchucks" are filled with candy, since her previous attempt with cookies didn't go well.
(Source: Anime News Network)