Bleach has been around for over fifteen years (as a manga; the anime was canceled in 2012, but is finally making a return sometime soon). It has garnered both critical praise and a cult following — becoming one of the best known series outside Japan. The arcs are formatted in the shōnen style, so the overall story is more or less predictable.
However, the sheer number of characters in Bleach is what makes it such a compelling show, as many of them have their own narratives and backstories, weaving in and out of the main plot. Two of the major ones are Aizen Sosuke, and Captain-Commander Yamamoto Genryusai, who happen to wield the most overpowered Zanpaktous in history. Fans have always wondered how they compared against each other — the list below offers an analysis of the two.
10 Kyoka Suigetsu Has No Weaknesses
When Aizen first revealed the powers of his zanpakuto to the Shinigami, he ensures that most of them are present at the viewing by pretending to explain the workings of Kyoka Suigetsu. Aizen claims that it is a flowing-water-type, able to distort images in a fog and cause enemies to fight amongst themselves.
Its true power, however, is Kanzen Saimin, or Perfect Hypnosis: it allows Aizen complete control over the viewer's five senses, or, in his words "make a dragon out of a fly; or a field of flowers out of a swamp."
9 Ryuujin Jakka Is The Most Powerful Zanpakuto
Yamamoto Genryusai is thousands of years old, and is the first of all the Shinigami. His zanpakuto follows his cue, by being the oldest as well as having the most offensive power in all of Soul Society.
It took Yama-jii all of half a second to wipe out the Driscoll Berci with a single swing, an incredible feat considering that Berci was in possession of Sasakibe's bankai at the time. As a testament to its capabilities, Aizen himself admits that he would not survive if he fought against it head-on.
8 Kyoka Suigetsu Is Wielded By Aizen
When the Captains are ganging up on Aizen in the Fake Karakura Town Arc, they issue warnings to each other about his zanpakuto's abilities. Ichimaru Gin, who is watching the battle from a distance, mocks them for not realizing that Kyoka Suigetsu is hardly the real threat.
In fact, the reason all the Captains lose is simply because of Aizen's terrifying Reiatsu level, as he displays by negating Suì-Fēng's Nigeki Kessatsu by generating more spiritual pressure than her technique.
7 Ryuujin Jakka’s Abilities Are Sophisticated
The old man has had a lot of time to perfect the nuances of his shikai, making it a weapon of both ultimate force and delicate finesse. For instance, Yamamoto traps Aizen, Gin, and Tosen in a massive fortress of fire, claiming there is no chance for them to escape.
In his fight with Ayon, he uses Nadegiri, a technique that slices the monster in half without him even realizing it (or even using fire.) Soon after, when the Tres Bestias pounce on him from above, he commends their bravery for fighting with only one arm, telling them that he will only leave them with only a "light toasting", which displays how much control he has over his zanpakuto.
6 Kyoka Suigetsu’s Effect Lasts Indefinitely
All it takes for Aizen to have everyone under his control is to let them watch while he utters the release command for Kyoka Suigetsu, "Shatter". After this event, he can delude them for the rest of time. This is shown when he exposes the use of his zanpakuto by having Hitsugaya stab Hinamori while making everyone believe it was him. This event is topped off by one of the coolest lines in Bleach history.
The only people who can, to a slight degree, see through his illusions are Unohana (who recognized that something was off with Aizen's "corpse" in the first arc), and Yamamoto (who can identify the presence of Aizen by his reiatsu.)
5 Ryuujin Jakka Is Unstoppable
Aizen understands that his goal of killing the Soul King will not be accomplished before destroying the Shinigami, which overall is a rather easy job for him. The tricky part is countering Yamamoto's Ryuujin Jakka, for which Aizen is forced to create alternative measures (in the form of a Wonderweiss, a modified Arrancar whose sole reason for existence is to nullify Ryuujin Jakka.)
Even during the Vandenreich invasion, Yhwach does not have the guts to fight him (because he remembers what happened when he fought Yamamoto a thousand years ago.) To even things out, Yhwach simply steals the Captain-Commander's bankai, leaving him vulnerable.
4 Kyoka Suigetsu Mirrors Aizen’s Personality
Captain Unohana refers to Aizen as a "traitorous criminal" when his actions at Central 46 are discovered, because of his callous deception of Soul Society. Like Kyoka Suigetsu, Aizen is a highly skilled manipulator, given that he managed to fool most of the Captains for over 200 hundred years.
This is not surprising because the spirit of a Shinigami's zanpaktou is an unconscious reflection of their soul. The danger this poses, however, is the union of Aizen and Kyoka Suigetsu, which allows them to maneuver the system any way they desire.
3 Ryuujin Jakka Is Not Essential To Yamamoto
Aizen scorns Yamamoto's reliance on Ryuujin Jakka, telling him that it took but a simple trick to defeat the old man. But when Wonderweiss charges at him, he easily sends him flying across an entire city block with a single punch. Yamamoto then scolds Aizen for assuming that his zanpakuto had any bearing on his own strength, proudly stating that he has been the Captain-Commander for over a thousand years.
Wonderweiss returns with a far more aggressive attack, delivering thousands of punches all over Yamamoto's unprotected body, a technique that most likely defeated Captain Kensei's punch-based bankai (and still leaves nothing more than scratches on Yama-jii).
2 Kyoka Suigetsu Can Fool Even Yhwach
Yhwach's biggest weakness is his cockiness, thinking that nobody in the world can match him after he absorbs the Soul King. The heroes put up a good fight, nevertheless, but their weak abilities are of no effect. However, things change drastically when Aizen joins the battle, setting off the most powerful Hado ever seen in the series, #99, Goryuutenmetsu.
Yhwach laughs at their feeble attempts against him, right as he impales Ichigo with his arm, breaking Tensa Zangetsu in the process. Aizen then reveals that Yhwach had fought him all along, telling him that Kyoka Suigetsu managed to outguess The Almighty — which distracts the latter for just enough time for Ichigo to swoop in.
1 Ryuujin Jakka Has A Bankai
Ryuujin Jakka's shikai alone can take out multiple opponents, as seen when Yama-jii effortlessly defeats Äs Nödt, NaNaNa Najahkoop, and Bazz-B (who had earlier defeated three Captains.) The bankai, Zanka no Tachi, has an overwhelming power that affects the fabric of Soul Society itself. Yamamoto himself is in a hurry to kill Yhwach and finish the battle, as he states that the alternative is the utter destruction of Soul Society and everything in it (including himself.)