Grim Reaper: Why Some Soul Reapers Never Recognize Ichigo's Father
Reaper: Millennium Blood War finally revealed Yixin's past as Reaper, but why did some characters never recognize him before?

Warning: Contains spoilers for Bleach: Thousand-Year Blood War episode 11.
Bleach finally explores the past of Ichigo's father, Isshin, which raises the question of why some of the soul reapers in the series never seem to recognize him. A multi-episode arc exploring Isshin's past began in Episode 11 of Bleach: It was revealed that Isshin was the captain of Squad 10 before Toshiro. There have been many hints throughout the series, but this is the first time that Isshin has been explicitly confirmed as Captain Bleach.
While receiving information about Isshin might be a good thing, in retrospect it does seem to have caused some problems for Kubo Tate's Bleach. There are a few times throughout the series that the Soul Reapers will recognize Yixin by his side, but there is no indication that they recognize him. On the surface, this might seem like a plot hole, but it turns out that Bleach creator Tite Kubo has already explained the biggest hole at length.
Why Bleach’s Rukia Never Recognized Isshin As A Soul Reaper?

The biggest question that needs to be addressed is why Rukia never seems to admit that Shinshin is Shinigami throughout the entire Grim Reaper. When Isshin was the captain, Rukia was the god of death, but They met several times, and there was never any indication that either of them felt familiar to the other. To make matters worse, Yixin is Kane's uncle. Hein's resemblance to Bleach protagonist Ichigo Kurosaki is mentioned several times in the series, so with the revelation that they are cousins, it seems odd that Rukia never thought they were related, since this is An easy conclusion to draw.
Luckily, Bleach creator Tite Kubo has explained it. In a Q&A on Kubo's official blog "Klub Outside", Kubo explains that since Rukia and Isshin are on different teams, they have barely seen each other, so Rukia has no reason to recognize Isshin. Kubo also reveals that soul reapers are generally infertile with humans (via YouTube), so even though Ichigo looks exactly like Hein, Rukia has no reason to believe it's just a coincidence, and Ichigo's performance further confirms this more than Isshin More like Masaki.
Why Bleach’s Toshiro & Rangiku Never Recognized Isshin As Their Captain

Another Shinigami issue that needs to be addressed is why Toshiro and Rangiku never admit that Isshin is one of the Shinigami captains. The revelation of Yixin's past also shows that Jun Lang and his wife have been together. Luanju was Yixin's subordinate when Yixin was the captain of Death God, but no one mentions it now. It's a completely different situation than Rukia, who never actually met Isshin, and the fact that they were even at Ichigo's house at one point felt all the more weird.
However, Tite Kubo also answered this question. In the interview with Kubo in the JET album, Kubo revealed that in the Shaman chapter and the Shinigami full manifester chapter, when he went to Karakura Town several times, Toshiro and Rangiku did recognize Isshin, but they didn’t say anything because They don't feel like it's none of their business (via Reddit). Both this and Rukia's situation could easily explain the problem, but anyway, the writer seems to have put some thought into this part of the story early on, which is fine.
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