[Chaos Zangetsu]

Originally Posted by sakuraame

I agree that from what we've been shown, Urahara is thought to be the mastermind behind the Hollow experiments. But that knowledge doesn't work with Isshin's presentation of his knowledge on the Vizards. Isshin calls them criminal shinigami that used illegal techniques to acquire hollow powers (I'm paraphrasing). That implies that the Vizards took it upon themselves to actively acquire hollow powers. And in Isshin's understanding, Urahara doesn't necessarily have to play a role. But we know that Central 46 thinks that Urahara experimented on his fellow shingami, turning them into hollows. That would make the Vizards victims. Actively seeking hollow powers and being victims of hollow experimentation are two different explanations that can't both be true. Also Urahara's role is key and I would think that Central 46 would see Urahara as much of a threat as the Vizards that he created, so how can Isshin talk so calmly to Urahara when Urahara is thought to be the mastermind

It's because Ishin knew the truth about what happened. He knew Aizen is the one who caused their hollowification. Urahara was involved however by using the Hongyoku(forget what it was spelled like)to stop them from being totally hollowfied thus the vizard were stuck halfway. This would imply that either he didn't know and Urahara told him about it or he kept tabs on Aizen and already knew what he was up to. I believe though that there was another report from Soul Society later on. Read after this next quote to know what I mean.

The fact that Isshin thinks that Vizard are criminal shinigami and not a product of hollowification experiments means that either only certain people know about Central 46's theory and everyone else was told something different or Central 46 changed their mind about what they thought Vizard were, going from victims to criminals, once they were able to control their hollows... or Kubo is confused. But something must have happened in between because what Isshin thinks Vizard are doesn't really jive with what really happened or with what Central 46 thinks happened.

I would guess that Central 46 originally thought they became complete hollows or died. Once they discovered that they were alive they wanted them dead so as to bury what happened or because they could present a danger to Soul Society. The Vizards found out the situation and they left Soul Society before they can be pursued.

Originally Posted by Kafriel

I haven't heard this one before, it could be possible...but Isshin had his powers sealed in the amulet which he ended up holding and eventually giving to Ichigo, so whoever sealed his powers did it on his command.

No, that was simply a ward to protect Ichigo and Kon especially. The only way that charm could've had any real impact on Isshin is if it gathered energy while in Soul Society or it drew on a miniscule part of Ichigo's power constantly while Ichigo wore it. That could've been used maybe to kick start Isshin to get the power to go out of the gigai. That would explain how he became a shinigami soon after Ichigo gave the charm back. However I still don't believe that could be the absolute case.

Originally Posted by churchblue

Isshin will fight Aizen soon after the Vaizards show up.

Isshin is probably the same level as Aizen.

Possibility but not likely. Isshin might fight Aizen eventually but will lose. It's usually the main character of the story to win against the main bad guy. It's always been Ichigo's job to kill the main bad guy so this time shouldn't be different than past arcs.