Board Thread:Improvements and Issues/@comment-5355747-20130313062554/@comment-6935068-20130709054052

Well, you know, if you have keen eyes, you might notice this while you're reading the manga. In Chapter 518, after Kukaku shot the pillar to the Spirit Palace, Ganju asks if Kukaku is alright Ichigo is going to the Spirit Palace.

Kukaku said if she didn't let Ichigo go, Soul Society will be destroyed at the next invasion. She let Ichigo go even if that means their uncle will be disappointed.

Surely you know who this 'uncle' is, right? Isshin Shiba was the head of the Shiba clan, as was revealed during his flashback. So that means Kaien, Kukaku, and Ganju Shiba are Ichigo's cousin.