Kimimaro. And no, Sai's brother has a name--we were given it by databook 3. It's Shin. And Kimimaro's history is pretty much spoken for. I would have loved that, though. :[

Yeah, I figured that there was definitive canon against it. I thought it would be a cool idea to play with, though.

I know! I was so thrilled when they showed up! It's tragic that we only got one chapter of them.