Kaoru Mitarai

The younger sister of Hiroshi Mitarai, Kaoru Mitarai is the culinary sibling with a serious infatuation over Ten-chan, who she loves a great deal- she often cooks for him or else plans weddings and marriage for him. She reacts violently to anybody who would dare to be mean to Ten-chan or Hiroshi- although she does value Takashi more than Hiroshi. She wears what appears to be a tape measure, tied into a bow, in her hair. Kaoru appears reasonably regularly in the anime; but extremely rarely in the manga (she is ditched from the cast page eventually, and is one of the only character who is). Her surname, like her brother's, can be translated to mean bathroom, and her first name means fragrant. In that interpretation, her full name means "fragrant bathroom." Ten-chan thought naming her that is like child-abuse. She often finishes her sentences with "desu wa" in the anime. Kaoru's seiyū is Sakura Nogawa.

Source: Wikipedia