User blog:Tekkphreke/Shikai and Bankai

I've been curious about something, I kind of noticed this when Shinji showed up in that last battle, also something about Yamamoto's final battle, it's been talked about how Captains have mastered their Bankai, the question I have is that is there truly an absolute limit to the strength of Bankais and for that matter Shikai. During the last battle that Shinji showed up for he mentioned he had been training his Shikai to be able to distort speech as well as perception of direction and so forth. Yamamoto had pointed out that over the 1000 years between his first and final battles with Yhwach his Bankai had changed and continued to grow even more powerful, though Yhwach stated he was weaker than when he faced him 1000 years ago. Also a kind of mindblower if you think about it, if someone focus's all their training into their Shikai and don't bother training up their Bankai's is it possible for the Shikai to become more powerful than their Bankai's or does the Bankai grow proportionately although the way it's been presented throughout the series is that one has to keep training on them both since they seem to pretty much act as separate types of powers (ie training on one doesn't necessarily affect the other) So final question on this, if a Shinigami continuously grows in spiritual power is there a true upper limit of their respective Shikai and Bankai?