Rinko Nikaido

Roxanne is the adopted daughter of Mari Nikaidō and is Mantaro's love interest. She attends Shirabara (白薔薇?) Private High School, Class 2-A. In the original manga she is a kogal and debuts after the Hercules Factory Second Year Replacement Matches, but in the anime she is a more wholesome high school girl who loves wrestling and first appears during the Tel Tel Boy fight. Her two best friends are Keiko and Tamaki (Kiki and Trixie in the anime versions) and they are almost always seen with her, although lately they have been fading into the background and she has been spending more time with Jacqueline.

Although she occasionally seems more interested in Jade or Chaos, she is generally considered Mantaro's girlfriend. wikipedia