Kaoru Matsubara is one of the three main heroes in The Power Puff Girls Z (alongside Momoko Akatsutsumi and Miyako Goutokuji). She transformed into her superhero alter ego Buttercup and her signature weapon is a piko piko hammer. She is voiced by Kelly Metzger who is also voiced Spitfire and Blossom Forth in My Little Pony series.
Kaoru was the third member of The Power Puff Girls Z. Her transformation is "Powered Buttercup" and uses a large swing hammer as a weapon. She is also skilled at martial arts.
Kaoru is famous for being the most athletic girl in school and is admired by many female students. She enjoys all kinds of sports and spends a great deal of time watching them on TV. It's shown she is mostly good at soccer. Kaoru's greatest fear is ghosts and haunted mansions.
Kaoru has a slight crush on Butch, as seen after her kiss until she was told to stop. She's represented by stars.