User blog comment:Godisme/My Take on Isshin/@comment-1393830-20100328181602

@BlazeItachi- we never said he left SS to protect Ichigo, my theory is he stole or was given an item like the hogyoku and left SS to protect it and then placed it in his son when he was a child. @NeoNirvana- exactly, that smile really clues us into Isshin's attitude and power. If he can show up to fight one of the most powerful shinigami ever with a smile on his face he has to be strong