I want to get right into it: I'm a big time Bleach fan. Thinking back now, I must have started watching it at first when it had just under a hundred episodes out. Probably another hundred episodes later and I finally started reading the manga as well. Doing a quick google for Bleach and wikipedia reveals that the anime started airing in late 2004 so even if I started watching it a year or two later, that's still a long time that I've been a fan of it so that should tell you a bit about what I think of the show. Basically, it's entertaining, it's about good and evil, the obvious fight that's always gonna rage between them but for me, what matters most is how it's more about getting the power to do anything you want and not just by stealing it or buying it cheap but by earning it and working hard for it then sticking with your original goals to the end while trying to achieve them. The things some might want to do with that power, good or evil, in the anime, it doesn't matter because what matters is how fascinating, how grandiose and how potent that power is and how it can reveal to you that the limits you once saw were perhaps just artificial. The anime characters, of course never realize this at first so that the fascination can go on for longer but eventually once they do realize that they have gone further than the sky, everything turns back to normal, the boring kind of normal. That's Bleach.
Now that I've told you why I like to watch and read Bleach, what I actually wanted to tell everyone were some thoughts I had that lead to some theories about what "Tite" Kubo might have in mind with this manga. Right now the manga is at chapter #453 and ever since Ichigo defeated Aizen, everyone seemed to have forgotten about Aizen. Nobody questions why he went so far and what was he actually aiming for. Was he really conceited in thinking that he was a God or did he really had what it took to become one eventually? I for one, know at least that he was pretty damn ugly before he died to look like what I think a God would look like but for others it may be different. Others don't need an angelic figure for a God because in the end just the power matters.
I don't want to start posing new questions but everything begs a question in Bleach right now more than ever. Defeating Aizen was the climax of the entire series and everyone had questions before it but now that everything is looking like a new beginning we can't ignore the questions left unanswered plus the new ones arising. So here's my theory on the series so far.
Aizen was about to tell Ichigo why he was interested in him so much ever since he was born when Isshin, Ichigo's father, interrupted him. Aizen said something like "...because after all, you are the son of a human and a...". What I believe he meant was "a hollow" or "a vizored".
Let's talk about the Hougyoku. Aizen again cleared some facts about it. The Hougyoku's powers weren't those of controlling the barrier between a hollow and a shinigami. That power was in fact a manifestation of it's actual powers: the Hougyoku can guide souls on the right path to achieving whatever they want as long as they themselves have the power and capability to achieve their goals. That's why, when Urahara Kisuke wanted to breach the wall he found between the two opposing sides of a soul, a shinigami and hollow arrancar, the Hougyoku he created, his Hougyoku, guided him towards that goal because: 1) it was possible and 2) Kisuke had the power to achieve it.
Aizen also used his own Hougyoku (some of you know that Aizen actually had developed his own), to drive Kuchiki Rukia into giving Ichigo her shinigami powers, basically jumpstarting his shinigami side. That's how Aizen realized that what he wanted, the Hougyoku helped achieve by bringing forth the opportunity for him to order her to the human world at the right time, when she was vulnerable after she had killed Shiba Kaien. Aizen said this himself.
So that's how the Vizoreds were born... except Ichigo. Ichigo's vizard side was born right after Urahara already had learned how to break the wall. When he shoved Ichigo into that deep well to turn into a hollow, telling him that by fighting it he could return back with his lost powers, he did that with that purpose in mind knowing that if it was probably impossible for anyone else, for Ichigo it might be possible because of Ichigo's mother who had a vizard/hollow side in her that she passed along to her son. I mean, if Ichigo got his Zangetsu persona from his father (Engetsu), he must have gotten his hollow persona from her mother. Ichigo possessed a mixture of different souls with very powerful wills that Urahara trusted Ichigo could balance out.
Before Ichigo got his enormous physical strength by evolving beyond bankai with his sword chain wrapping around his arm, Isshin also showed enormous physical strength when he fought Aizen and threw what was like a flick of the finger attack at him sending him flying through three buildings. Right after that fight, when he spent time in the precipice world helping Ichigo learn the Final Tensa Zangetsu which is basically two exponential evolutions up from Shikai and Bankai, he told Ichigo that he once also learned his Final Tensa Engetsu. Then we also know that Isshin supposedly lost his powers but it was revealed that he was getting them back around the time Ichigo started fighting with Grimmjow. Perhaps he lost his powers because of using his Final Engetsu or maybe he didn't loose them at all and they were only weakened by the years he spent wearing Urahara's reiatsu blocking gigai.
While this was a lot for me to think about right now, I still have a few theories popping up every time something new is revealed in the manga and it's easier to think about them then than trying to make sense of all of them now. I would like to end this post that's already become too long by saying that I think Kubo is definitely trying to reveal a big picture slowly but not entirely easy which is why this show is going to be memorable.