With the Bruce Lee-ish fighter Katsu's dad killed, I'd thought the crow kid would be his son, with the whole Brandon Lee thing and all. But after Katsu started becoming an offensive fighter and it showed Katsu's mom watching all of the Bruce Lee-ish fighter's fights, it became obvious. It's shameless to marry the fiancee of the man he killed, so there had to be a catch. Katsu's "dad" married the fiancee of the dead father, adopted his son, and took the fiancee's name. I suppose that's the least one can do for killing a fighter with potential.

I still wonder about the crow kid though. He could've been there to trick people, but I think there might be more to it.