Board Thread:General Discussion/@comment-10587310-20130620070434/@comment-5398287-20140108224950

The "ultimate form" used by Ichigo isn't really a Bankai 2nd stage, just the appearance of his Bankai after he learned how to use Saigo no Getsuga Tenshou. But yeah, both of those ideas are very silly. Additionally, neither snake nor baboons have wings, so that wouldn't make any sense for Renji's Bankai.