Now that I've finished overhauling every episode page for the Zanpakutō and Tōjū arcs, I've realized that both arcs are nowhere near as bad as I thought they were going to be. However, since they each still have their own low points, I thought I'd make a review of both arcs that covers their ups & downs in various aspects. This will be divided into two sections: a Zanpakutō arc section and a Tōjū arc section, since they're technically separate and have different things going for them.
Zanpakutō Unknown Tales arc
Out of the two arcs, this is by far the better. For starters, it had an actual storyline (the Tōjū arc was mostly a bunch of slice-of-life episodes strung together), a pretty unique and interesting concept for a Bleach filler arc, and a plot that had an air of mystery to it (Why did Muramasa kill his master? What are his real intentions? How the hell is Byakuya doing this in a filler arc?). Even though it fell through quite a few times, most notably toward the end, I think this arc actually turned out pretty well given how it could've gone.
As the title of the arc implies, almost all of the new characters introduced are Zanpakutō spirits, who have been manifested in real world by Muramasa, himself a Zanpakutō spirit as well. It seems manifesting them like this gives them a different, more humanoid form when compared to what they actually look like within their Shinigami's inner world, as 1. Zabimaru went from being a baboon with a snake for a tail to a monkey-woman and a snake-child, and 2. a majority of the Shinigami don't recognize their Zanpakutō spirits on sight, and instead need some sort of visual confirmation (e.g. the powers they use, the way they act). The exception to this is Zangetsu, who remains identical to his inner world appearance either because he already looked human, or because Ichigo is Ichigo, take your pick. In my opinion, this was a good idea on the part of the producers because this way, Kubo wouldn't have to conform to whatever they came up with if he decided to show off any other Zanpakutō spirits in the manga; I know that it's filler and it wouldn't matter anyway, but still.
As for the characters themselves, I feel most of them fit what little we canonically know about them and their masters pretty well: Haineko is stubborn and kind of bratty, Hōzukimaru is lazy, Hyōrinmaru is stoic, so on and so forth. A couple don't make sense initially (Sode no Shirayuki is almost nothing like Rukia early on), but after they get freed from Muramasa's brainwashing, they act more like their masters, which is good. At least they provided something of an explanation instead of going "Senbonzakura is evil for evil's sake" or something along those lines. However, Muramasa and Kōga require separate analyses.
Muramasa is one of the more unique filler villains because he's actually trying to help someone other than himself. He is only really "evil" because he's trying to rescue Kōga; if things had gone down differently, he would've been a pretty cool guy. Additionally, you can occasionally see moments of humanity in him; when Orihime is confronting him about the pain stemming from his relationship with Kōga, Muramasa's expression grows noticeably sadder and softer, even if only for a moment. It makes him quite a sympathetic villain when it comes down to it; he just wants to help Kōga, but a sort of Stockholm's Syndrome blinds him to the truth until the very end and leads him to his downfall. Even though he undergoes an incredibly OP and stupid transformation in one of the last episodes, the last episode of the arc reestablishes that he's not bad to the core, and I like that.
Kōga, on the other hand...
I really like what Pierrot did with Kōga's character, don't get me wrong. He was an innocent, if a bit prideful, and powerful Shinigami who was the victim of a conspiracy, but he quickly spiraled down into insanity after slaughtering the conspirators. The whole thing is very Shakespearean, especially his deteriorating relationship with Muramasa (somewhat reminiscent of one of the themes of Macbeth, imo), and just like Muramasa, it establishes him as a villain that's not evil for the sake of power, at least not initially. However, what I, and a majority of the fanbase, absolutely cannot STAND is how incredibly overpowered he is.
He uses fairly powerful Kidō like it's nothing, that's fine. He's a master swordsman, that's fine. He's a Shunpo master, that's fine. But putting that all into one character? How is that even remotely fair? And that's not even mentioning that fact that 1. he had vastly more Reiryoku than Ginrei, an actual member of the Kuchiki Clan and a fairly powerful captain, had while he was still only a 3rd seat, and 2. he was able to use Muramasa's illusion and spiritual thread abilities by himself and without Muramasa's aid AT ALL. He even claimed that he GAVE those abilities to Muramasa. Even though he started out as par for the course with filler villains, he quickly went from standard to ridiculous to ludicrous
speed. Doesn't help that he was pretty much shoehorned in at the end of the arc without having been mentioned for a majority of it.
Best New Character: Kazeshini
Even though most of the other Zanpakutō spirits fit their canon descriptions fairly well, Kazeshini is by far my favorite of them all. He fits the hints that were given about his nature in the manga to a T, and he actually resembles the shadowy figure seen in the volume sketch after Hisagi releases his Zanpakutō against Findorr, which helps. Additionally, he has, in my opinion, the best-defined personality and motivations of all of the Zanpakutō spirits, sans perhaps Muramasa: he lives to kill other living beings, will never stop once he chooses a target until they're dead, and retains this personality even after being freed from Muramasa's brainwashing. To top this all off, his voice actor (at least his English one) does a very good job in delivering every line he speaks. Granted, he does become less of a maniacal badass in the following arc and learns to care for others and stuff, but even then he's still good because he receives good character development.
Worst New Character: Kōga Kuchiki
As you may have guessed from my previous rant, Kōga's overall execution is bad. Even though he had a strong start and possibility for sympathetic villain greatness, he ends up turning into a ludicrously overpowered villain with intentions almost completely unrelated to his experience and a knack for being an INCREDIBLY bad person. Seriously, what he did to Muramasa was almost painful to watch. You dun screwed up, Pierrot. You dun screwed up.
To be honest, this arc's storyline had the most potential out of all of them. The idea that we'd be able to see the Zanpakutō spirits that Kubo had been unable to properly show in the manga was an exciting one, and the premise that things weren't all hunky-dory between them and their masters was interesting. And for a while, it lived up to that in full. In all of the episodes prior to 245, the arc explored the relationship between Shinigami and Zanpakutō spirit in some really cool ways, and actually gave some characters legitimate character development upon realization of their flaws, Renji being a prime example. Additionally, the Shinigami initially being unable to use Shikai and never being able to use Bankai unless they forced their rogue Zanpakutō spirit to submit was done well because it was logical; if a Zanpakutō spirit isn't in the sword, then there's no way a Shinigami could access its true form properly. It was a properly done way of forcing the Shinigami to fight in new ways and make them weaker in order to fight on similar levels to their enemies, unlike what a certain final filler arc did. Things were going good for quite some time.
But then, we reached Yamamoto's rescue, and things started deteriorating. Don't get me wrong, there was still some really good stuff between this event and the end of the arc (Kōga and Muramasa's troubled relationship in particular) and the fights were pretty good, but it felt like the arc had lost some of its purpose. Now Shinigami were accessing their Shikai without having gone through a personal revelation of any sort, Muramasa's plan became much more convoluted, and Muramasa himself became much more of an asshat by revealing he had lied to all of the Zanpakutō spirits in order to use them. Kōga's backstory was interesting, but his present-day self was as unlikeable as could be, and Muramasa's transformation was so BS that I'm reserving my rant for later. The ending wasn't too bad, since it had Muramasa return to form and gave us a really sad moment, but by jove did things derail prior.
Best Moment: Kenpachi's Arrival
This got me the most excited for an episode out of all of the other big moments. Kenpachi stays completely true to form by showing up and doing what he does best: kicking ass and displaying his ridiculous power. First, he demonstrates his caliber by blowing up a building with his Reiatsu and effortlessly defeating Wabisuke. Then, he literally BLOWS AWAY all of the other combatants sans Byakuya in what essentially amounts to a small nuclear explosion. And then, after he leaves a crater a mile wide, he engages in a fight we had all been waiting for: Kenpachi vs. Byakuya. Not any of that teasing crap that happened during the Yammy fight, mind you; they crossed blades, hurt each other quite a bit, and were really getting into it. Even though it sadly got interrupted during the next episode by Konjiki Ashisogi Jizō, ye gods was it awesome. It's too bad that this was the last episode before the arc started sliding downhill, but man was it worth it.
Worst Moment: Muramasa's Transformation
Remember that vague transformation I alluded to prior? Well, in episode 253, Muramasa finally loses control of the Hollows he had been absorbing to maintain his physical form. Does this tear him apart from the inside out? Unleash all the Hollows and leave him comatose? No, it transforms Muramasa INTO A HOLLOW HIMSELF. That's right, a Zanpakutō spirit becomes HOLLOWFIED. How this is even POSSIBLE is beyond me. And to make it worse, he's even MORE overpowered in this form. He rolls around at the speed of sound, fires Cero and Bala that decimate captain- and lieutenant-level combatants, and has a spiritual power that can destroy Karakura Town. Oh, and he eventually turns into a weird, red-black dome that unleashes tons of Gillians and threatens to consume the Human World. Way to drop the ball, Zanpakutō arc.
Despite the rather glaring flaws that emerged near the end of the arc, I still think the Zanpakutō arc is very good. It brought something new to the table with the Zanpakutō spirits, it had a storyline that remained fairly interesting throughout, and it was full of some very awesome moments.
Now, this arc is essentially an extension of the previous arc and keeps most of the new characters, but it has its own premise and storyline (if you can call it that), so I'll be discussing it separately. As I said before, I consider the Zanpakutō arc to be the better of the two due to having a far more solid storyline and premise. However, even though I initially thought this arc would be annoying and pointless, I found myself liking it for its humor and additional character development.
Almost all of the new characters introduced in this arc are the eponymous Tōjū, and they're...interesting, to put it tacitly. While some are pretty cool in concept and execution, others feel forced and unnecessary. One thing that I don't like about all of them is that they're supposedly always in Bankai because they're free. While it makes sense for the producers to do this so they actually stand a chance against a lieutenant or captain, since they're the rogue Zanpakutō of unseated Shinigami and thus wouldn't be very powerful at all in their regular forms, it doesn't really show in their fights. I know they're not very powerful to begin with, but I would assume the Bankai of even a somewhat weak Tōjū would be enough to allow it to hold its own for some time. However, though this is occasionally displayed properly when a Tōjū holds its own against a lieutenant-level combatant, most of the time they're just fodder. Fodder that are faster and stronger than usual, but fodder.
You may have noticed that I said "most" of the new characters are Tōjū. As it turns out (and I wasn't expecting this either), they included one new Zanpakutō spirit in this arc: Hisagomaru. Though he only appears for about a sixth of one episode, Hisagomaru is an example of a manifested Zanpakutō spirit done (mostly) properly: he's timid and apologetic just like Hanatarō, and certainly looks like what the spirit of Hanatarō's sword would probably look like. The only real gripe I have with him is his Akeiro Hisagomaru ability: rather than just unleashing an energy wave composed of all the injuries he's healed at his target, Hisagomaru instead pulls an enormous cannon out of nowhere and fires an energy beam. I understand that this is an instance of the producers trying to make the Zanpakutō spirits not exactly like their canon counterparts in terms of abilities, and I respect that, but I feel it could've been done a bit better.
Best New Character: Narunosuke
Narunosuke is the only example of a Tōjū that one can actually feel sympathy for. He legitimately wants to be normal and not get hunted by the Shinigami, and is actually sane for a majority of the episode. He's a nice guy who just wants to live without fear of being hunted. Plus, his relationship with Haineko makes for some heartwarming moments and some hilarious moments as well, like when a Haineko acts nicely toward a shocked Rangiku after being complimented by Narunosuke. And even after he goes berserk, there's something sad about him because you may have been rooting for him to become normal instead of succumbing to the same fate as the other Tōjū. And his last words when he regains his sanity? I almost cried, I really did.
Worst New Character: Kirikaze
If you need a textbook example of how a Tōjū can be done wrong, look no further. His badness begins when the Zanpakutō spirits reveal they've been tracking him despite this having NEVER been hinted at in previous episodes. Then, they explain how he has the ability to absorb the Reiryoku of other Tōjū to make himself stronger, and can continue to do this indefinitely. And THEN, when the fight against him finally begins, he proves just how overpowered his ability to turn into mist really is. He consistently dodges attacks, overpowers captain-class Zanpakutō spirits, and even reverses the absorption flow of Ruri'iro Kujaku. My lord, is it catharsis when Renji utterly obliterates him with Hikotsu Taihō.
As I said before, this arc doesn't have a solidly presented storyline. The general gist is that the Shinigami are hunting down and killing rogue Zanpakutō spirits and researching them. Though this is generally present in all of the episodes, it takes a backseat to displaying and expanding upon the relationships between various characters. However, in relation to the content of the previous arc, I think this was a good call. We got to see the true nature of the Zanpakutō spirits because they were no longer under Muramasa's brainwashing, and we saw more of the interactions between Zanpakutō spirit and Shinigami that we wouldn't have been able to see during the Zanpakutō arc because it would've interrupted the momentum. So, in that respect, I think it was pretty well executed.
Best Moment: Episode 263
Pretty much all of episode 263 is amazing in different ways. First, we learn that Senbonzakura isn't the high-and-mighty guy he pretends to be after he smashes a hole through the SRDI walls in order to enter. Then, we learn that he's also kind of an idiot when he traps himself and Saru and Hebi within the SRDI and refuses to accept the blame. THEN, we get some good comedy when Ashisogi Jizō royally pisses off Senbonzakura by bringing him a banana instead of the remote control...which it then accidentally smashes. THEN, Senbonzakura's mask is damaged and breaks apart completely...prompting him to pull another one out of nowhere and put it on while the camera remains teasingly focused on the lower half of his face. THEN, Senbonzakura causes even more mayhem by pressing several buttons in a secret lab, culminating in Renji's bathhouse blowing up, Rangiku and Haineko faceplanting on treadmills, and Byakuya giving an epic death stare to the Shinigami Women's Association after finding out they were still meeting in his house. And THEN, Senbonzakura believes Konjiki Ashisogi Jizō has challenged him and starts fighting with his Bankai. The ensuing destruction pisses off Saru so much that she activates her and Hebi's OWN Bankai and destroys the entire SRDI with Hikotsu Taihō. All of this, coupled with the hilariously bad animation for Renji's reaction to the explosion, makes this episode pure gold in my book.
To be honest, I can't think of a single moment that was outstandingly bad within the arc. Sure, there were some concepts and characters that weren't executed very well or weren't fleshed out as much as they could, but there was nothing on the scale of or relative to Muramasa's transformation or Kōga being Kōga. Take that as you will.
The Tōjū arc, while not as solid as the Zanpakutō arc, ended up being pretty good, all things considered. It provided some much-needed character development and comic relief, yet managed to retain a serious tone when it needed to.
These two arcs were nowhere near as bad as I was expecting. While they both fell through in certain areas and forgot about others as time went on, I feel they did the best they could. Additionally, I feel they both serve different purposes, yet work together in certain ways, a rare feat for filler arcs.