The main character of the series. Momoko is a member of the schools disciplinary committee which is a duty that she takes very seriously and often puts her at odds with Shinobu. She is very gluttonous (though never seems to gain any weight), irritable, and has very little tolerance for other peoples antics (though she is shown to have a mischievous side of her own). She is kind to her classmates however which makes her very popular.
Momoko always wears a rather strong-smelling perfume which usually gives away her presence before she even makes it known. Several years before the series she first met Shinobu in a park when they both were very young. Shinobu gave her a cookie and Momoko in return gave her a kiss. This encounter left Shinobu with deep feelings of love for Momoko, though Momoko does not remember at all.
Momoko finds it hard to warm up to Shinobu due to latters promiscuity, but later reciprocates her feelings after realizing that Shinobu is genuinly kind and truly loves her. She even hits an upperclassman, who had forced herself on Shinobu, with a fire extinguisher.