He is Ryouko's partner, acting as her driver and bodyguard while she researches quantum phenomena. He doesn't understand the bulk of Ryouko's work, asking for simplistic explanations here and there, but he sticks around her anyway. He does get to shine at the very end of the series when timespaces are converging and a corrupt corporate leader refuses to let Ryouko stop it. He shoots Kouriyama, only to find that he's unaffected because "apparently there's a me that doesn't get shot!" Kouriyama remains unhurt after the timespaces separate. (Source: Wikipedia)