Board Thread:Improvements and Issues/@comment-5355747-20130313062554/@comment-11051098-20130709132155

I have noticed that, yes. It's obvious now that Isshin is the uncle, which makes Kukaku and Ganju Ichigo's cousins. And I noticed how Byakuya and Ukitake recognized Kaien in him back then on the bridge to the tower Rukia was held in. But no one knew who his father really were back then.

Maybe Kukaku eventually came to the conclusion, I don't think Ganju did, not back then at least. She must have known, or at least suspected, that Isshin was in the human world all those years. But there's a difference between Kukaku and the captains and lieutenants. I don't know if anyone beside Rangiku and Hitsugaya, who were Isshin's subordinates, would have noticed, and even they seemed to have missed it.