Board Thread:General Discussion/@comment-4976518-20140808063123/@comment-29325824-20200512083117

SIGH I'm getting tired of this discussion. There is no proof at all Aizen does not have Bankai. It's like saying "Ukitake has no Bankai becasue we never saw him use it".

See, there are so many reasons Aizen chose to never use it. It could be simply way to impractical, dangerous, and/or inefficient to use. It could be unsuited for direct combat. It could be that merely activating it removes the Hypnosis of his (extremely useful) Shikai.

Who knows? But as was clearly stated, Kenpachi Zaraki was the ONLY Shinigami to ever become captain without a Bankai. And even that does not count anymore.