He is 15 years old at the start of the series and is from South Africa, although his name is Japanese. He uses Capoeira, the Brazilian style of martial arts that uses feet and dancing as the basis of combat. He enjoys fighting and is considered physically the strongest fighter of the group, although not the most powerful.
He has a girlfriend by the name Chiaki Konoike, who often enjoys having sex with him to the point where she has asks Bob to quit school so they coud have sex and wake up at noon. At the end of the series, 5 years after the start of the series, he marries Chiaki and has a daughter with her.