In Bleach, did Isshin become a captain after Urahara was exiled? If not, then where was he when Hirako and the others were getting beaten up by Aizen?

Question

I am a little confused about the timeline in Bleach.

I know that sometime after Urahara was exiled, Isshin went to the living world and fought that Vasto Lorde, and then Aizen stabbed him from behind, etc. But where was Isshin before Urahara got exiled?

I did not see him in the captains' meeting when Hirako, etc. were sent to the forest where Shinigami were disappearing. If he was not the captain of squad 10 at that time, then who was?

Answer 1

10th division had no captain when Urahara was instated as captain of the 12th division, and the post (most likely) had yet to be filled by the time Urahara was exiled.

In volume 36, during the "Turn Back the Pendulum" mini-arc set 110 years prior to the start of the series, during the time leading up to Urahara's inauguration, the captains discuss the present state of affairs. They mention things such as:

• 11th company's captain, Kenpachi (the 10th Kenpachi, i.e. the one before Zaraki), is slacking off, which explains his absence throughout the arc;
• 12th company's previous captain was promoted, hence why Urahara has been appointed as captain;
• and 10th company's captain has died.

All active captains were summoned twice during the arc: once during the inauguration of Urahara, and then at the climax of the arc when Captain Commander Yamamoto is responding to the disappearance of 9th division's investigation team. In both instances, squad 10 lacked a delegate; this strongly implies the post is vacant.

We do not know when Isshin Shiba (later Kurosaki) was appointed captain of 10th company, but we do know when he left the post: 20 years prior to the start of the series, and 90 years after Urahara was exiled.

This is expanded upon in chapter 529 onwards, which shows

Isshin investigating a mysterious series of Shinigami deaths, fighting a prototype Arrancar, getting backstabbed by Aizen, meeting Masaki, giving up his soul reaper powers, and settling in the human world.