User blog comment:Kingdeadpool/Byakuya and Kouga/@comment-1747976-20091225215343

I have been saying this for a while now. Everyone has disagreed with only one person saying 'maybe..' It makes sense as Gin Rei is his grandfather, this would make his daughter Byakuya's mother and Kouga, his father. Perhaps the reason Muramasa doesn't know who he is or Kouga is that he got sealed away when Gin Rei's daughter was prego. That can be the only explanation. It makes sense as well. Even though you will hear that a filler arc cannot in any way change the Bleach Universe or at least not permanently.