Giorno Giovanna is Dio's son and the fifth JoJo, though that's not important. I haven't gotten to part five yet, so I don't know what he's like in the anime, but here, he's a fairly normal teen trying to live a normal life but can't because of his insane father. He should have a teen sounding voice, of course. Not too deep or high. In the medium area. He should also usually have a sort of angsty tone seeing as how he's going through those years. His more conversational bits should seem almost forced, like he's a bit of a psycho underneath.