I don't know if two streets is necessary. The Yakuza tend to be very organized, comparable to the Italian mob in terms of 'legitimacy' and organization. They have families, that people might be born into; they also take thugs who were exiled or abandoned by their parents during high school or whatever.
So you could have a normal life situation, like:
DC; White Collar; Adolescent Warfare; House Training; Organized Crime
So that it's a story of a kid who grew up in a nice household with middle class parents, but that kid took up a life of violence in a local gang. He was taken up by the Yakuza, trained for some large-scale violence in power armor, and has been operating for them ever since.
Not that I think the Yakuza would have need for battle armor. Gambling, legitimate business, and protection rackets rarely call for 'em... but I suppose they might need battle armor users, in which case, yeah, I like the line I suggested.
