Koichi has been sent on a mission by Jotaro Kujo to find a man in Italy, known as "Hiruno Shiobana," and is supposed to investigate on wether or not he's a threat to people. He unknowingly meets him after landing at the airport, as he is hustled into having his money (and luggage) stolen. 

He is kind, and gentle, usually not trying to harm even his opponents. However, on some occasions, he can be aggressive, and vulgar. He is rather short, looking similar to that of a twelve year old boy, rather than a seventeen year old, and so he should sound a bit on the younger side. He really only appears for the first volume.