I always considered it a bit of a plothole(But what fucking isn't in Bleach?) that none of the fifty odd Shinigami Captains, Lieutenants, and Grunts which were downed during the Aizen battles didn't even seem to notice that Isshin was even there. Not one of them even stated afterwards: Who the fuck was that guy who could taken on Aizen 1 v 1 and put him through a building by flipping him in the forehead by a single finger? That's on the level of Yamamoto and these ridiculous royal guard, so HOW DID NOONE FUCKING NOTICE? And yeah I'm aware that he hides his reiatsu super well in Shinigami mode, that doesn't mean he can make it so he's invisible to them if they just fucking look up.We always knew Isshin's last name wasn't truly Kurosaki. If it was, everyone in Soul Society would have KNOWN who Ichigo was, as they would have remembered a Captain Kurosaki. We're still under the impression that Isshin ran, abandoned or is in hiding from Soul Society, so him taking up his wife's name (probably the woman he abandoned all of that for) isn't too far-fetched.
Unless she was from the mysterious FASCIST QUINCY WORLD(Oh sorry, the Vanderreich, what the fuck ever) which is making all of these fucking new Quincies immortal apparently.Isshin must have been a recent captain since he met Ichigo's mom who was a human, so he couldn't have been one centuries ago.
Isshin Shiba obviously.
Seriously, Kubo must be lurking Rerolled for his plot. Christ.Asmadai_sl said:After a little research its possible Isshin is from the 10th Division. Little is known about their history, and its known they hadn't had a Captain prior to Toshiro's promotion in a while. Shunsui/Unohana both claimed the former Captain died.
You know Urahara probaby had a hand in this with his Gigai. He probably made it so it erased memories of Isshin when she donned the suit. According to the wikia Rukia has been part of the gotei for at least 40 years prior to her encounter with Ichigo so it is for certain that she would have been aware of Isshin.Hang on a second... so wouldn't Rukia know on sight her best friend's relative who was one of the Captains? Didn't she live with him in the first Manga Arc and didn't say a word!?