Rio is a very dangerous Blade Child despite her child like appearance.
She is known as one of Kiyotaka Narumi's favorite and is Kousuke Asazuki's partner in crime.
Rio appears to be innocent looking, but is actually very intelligent and deceiving.Ryouko Takamachi according to Kousuke, is inferior to Rio in many ways and cannot believe it when they first met.
Her talent is creating home-made bombs, giving her the nick-name the"Fire Pixie".
Rio has a crush on Eyes Ruthford who gives her "net patterned" melons.