Beast Swords arc

The Beast Swords arc is an anime-exclusive mini-arc focusing on the Tōjū, Zanpakutō spirits that were materialized by Muramasa, but were not saved by their Shinigami, causing them to go into a blind rampage.

The Tōjū Appear
A party is being held at Byakuya Kuchiki's mansion for the Sixth Division. Renji Abarai thinks this is a good time for the division members to fraternize with their captain, while Rukia Kuchiki notices how nervous everyone looks. Renji is surprised that Byakuya is hosting the party in his own home, while Rukia says he should be grateful Byakuya's looking after his men. Renji is whisked off by one of his underlings while Rukia is lecturing him. Annoyed, she returns to her quarters, when she hears a scream. She investigates, and discovers two interlopers smashing up one of the rooms. She moves to engage them, but remembers she doesn't have her Zanpakutō. She narrowly avoids their attacks, until Sode no Shirayuki arrives. She drives off one of them, but is ambushed when she tries to prevent him from escaping. She is saved by Senbonzakura. Rukia is shocked to see them in spirit form again and they tell her they never agreed to just be swords. Their argument is cut short by Byakuya's arrival, and one of the interlopers body combusts, revealing a Zanpakutō.

Rukia, Byakuya, and their Zanpakutō spirits go over to Mayuri Kurotsuchi's place to ask him why there are still some Zanpakutō spirits around. He reveals that he never intended to return the spirits to Zanpakutō form. He continues to explain that the Zanpakutō that they encountered before were Zanpakutō spirits that were freed from Muramasa but they succeeded in killing their masters. While this would normally kill the Zanpakutō too, these are abnormal. Mayuri identifies this as something new; he names the new phenomenon Tōjū and tasks Rukia with capturing the one that escaped earlier. Mayuri warns them that the Tōjū have full access to their abilities and are effectively in constant Bankai.

Rukia ponders the difficulty of the task, but Senbonzakura and Sode no Shirayuki are both keen to fight. Renji arrives to inform them of a change of guard. Byakuya leaves Rukia in charge while he deals with this. Senbonzakura and Sode no Shirayuki both suggest large scale destruction to lure out the target but Rukia quickly discounts this. Sode no Shirayuki suggests that they have another party, this time at Tenth Division's headquarters.

Toshiro Hitsugaya is not happy with this, but allows it anyway since everyone needs a well deserved break from the battle with Muramasa. The plan fails however, as there is no sign of the target.

Rukia and Sode no Shirayuki have a quiet chat afterwards. Sode no Shirayuki reveals her inner turmoil regarding the events revolving around Muramasa. Rukia tries to remind her of the times when it was her who needed saving. This is cut short however when one of the Tōjū from earlier arrives. Capturing him proves more difficult when he assumes a tornado-like form but they are able to defeat him with a combination of her Shikai abilities and Kidō.

Rukia reports to Shunsui Kyōraku and Jushiro Ukitake that the Tōjū were delivered to the Shinigami Research and Development Institute and Ukitake reveals that similar reports are coming in from elsewhere.

Tōjū In The Human World
Before long the Tōjū begin to slip into the Human World. The first to cross over appears to be in a bad shape, due to the separation from his master. He enters the Human World next to a large construction sight in Karakura Town and soon runs into Substitute Shinigami Ichigo Kurosaki. The latter is puzzled by this strange new being and defends himself when the Tōjū attacks. Tōshirō Hitsugaya, who followed the Tōjū, attempts to cut him down but the Tōjū, though injured, makes a getaway.

Hitsugaya is briefing Ichigo and Kisuke Urahara about the goings on in Soul Society and of the existence of the Tōjū, when they hear the ruckus of a heated argument from the hallway. Rangiku Matsumoto and her Zanpakutō, Haineko have come to the Human world after their captain and despite his orders. Haineko quickly invokes the envy and rivalry of Ririn, who is nonetheless powerless to do any real damage to the Zanpakutō spirit. Rangiku and Haineko have been busy taking sexy photographs of themselves, which garner much interest from most of the male population of the Urahara Shop. Hitsugaya quickly loses his patience for his two underlings.

Back at Seireitei, Kyōraku and Ukitake are busy entertaining their Zanpakutō spirits. They agree between them that while they don't mind the Zanpakutō spirits being out, the Tōjū have nowhere to go. Besides, they decide, it's much more natural for the spirits to be inside the swords. Hearing this, Katen Kyōkotsu and Sōgyo no Kotowari punish their "masters". Sode no Shirayuki tells Rukia just how effective Captain Kurotsuchi was in bringing the Zanpakutō spirits out of Muramasa's hypnosis.

It is explained that when a Shinigami calls out his Zanpakutō's name, they resonate with each other and are able to fight as one. Muramasa's brainwashing destabilized the resonance and stimulation in the affected spirits, and Kurotsuchi discovered a way to re-stabilize them. Ukitake and Kyōraku, wanting to push Kurotsuchi to further research into the Tōjū problem, send Nanao Ise to him with a box of cakes. The captain accepts the cakes, but takes his time starting the research because the subject doesn't peek his curiosity.

Over in Karakura, the lost Tōjū is in trouble; a large Hollow spots and attacks him. The Tōjū tries to run away, but the Hollow catches up to him and devours him. Hitsugaya and Hyōrinmaru sense his presence for a moment but lose it the next, and Hitsugaya prefers not to call Matsumoto and Haineko, saying they would only make things worse.

In her house, Orihime Inoue finds Haineko too cute for words, in a Karakura High School girl's uniform. The three go on a girls night out but Rangiku uses it to track the Tōjū. She senses his presence in a skyscraper still under construction, but notes that it has somehow changed. They head out for the tower at about the same time as Ichigo, who is patrolling nearby.

As Rangiku arrives at the tower she realizes the Reiatsu can't be that of a Tōjū. Haineko spots a strange creature, standing above them on top of several steel beams suspended from a crane. The creature is an upright standing Hollow holding a spear like weapon in his hand. Before Rangiku can ingest her Soul Candy, the Tōjū cuts the straps holding the beams, and Haineko grabs her and pulls her to safety, causing Rangiku to drop the Soul Candy. Orihime uses Santen Kesshun to protect them from the falling beams. Haineko volunteers to deal with the strange Hollow but before she can react the creature attacks and pins her to a wall, demanding she returns his master to him. Just as the Hollow is about to strike, Ichigo arrives and cuts his arm, freeing Haineko.

The Hollow runs away and Ichigo follows and manages to cut him off on the arm of the crane. Zangetsu tells Ichigo that the Hollow is in fact the Zanpakutō from before, who has been absorbed by a Hollow and fused with it. When the creature attacks again, Ichigo knocks his weapon away and intends to use Getsuga Tenshō, but the creature launches a powerful Cero that Ichigo can barely block. Hitsugaya himself arrives to finish the job by releasing Hyōrinmaru and freezing the creature. The Tōjū's weapon breaks, noting that the tortured spirit is now dead. Hitsugaya warns Ichigo and the others that the Tōjū will prove to be a most troublesome foe.

Sometime later, Renji and Zabimaru arrive in the Human World to deal with the Toju. They stumble upon one, but Zabimaru's snake half goofs off and the Toju escapes. When the snake finds the Toju again, the latter tricks the snake into going off on his own so that the Toju can kill the two Zabimaru separately. The Toju once again escapes just as Renji and Zabimaru's baboon half catch up. The baboon scolds the snake which causes him to run away. Overjoyed to finally be by himself, the snake Zabimaru goes around Karakura trying to buy food, but canot obtain anything because most of the town's humans are not spiritually aware. When the snake stops at a conveiniece store, Karin and Yuzu Kurosaki find him and brings him to their home. Ichigo finds the snake and concludes that Renji is in the Human World. That night, the snake goes out to confront the Toju from earlier. Despite his determination, Zabimaru finds himself outclassed and is almost killed by the Toju. Renji and Zabimaru's baboon half arrives and finishes the Toju. The snake half gives a silent goodbye to Karin and askes Ichigo not to tell his sister that he left. With that, Both Zabimaru and Renji return to Soul Society.

Sewer Fight
Back in Soul Society, Nanao Ise and Isane Kotetsu notice several items from the 4th Division HQ have gone missing. Hanatarō Yamada also reports that several chickens he was raising have vanished as well. Suspecting it to be the work of a Toju, Retsu Unohana and Shunsui Kyōraku send Nanao and Hanataro, along with Ikkaku Madarame and his Zanpakuto Hōzukimaru, to investigate the underground waterways (while secretly keeping an eye on them from the Research Department with Akon).

In the sewers, while hunting, Hanataro accidently triggers a trap which causes a large amount of water to wisk them to a large open chamber. While they argue, Ikkaku is grabbed by a large tenticle and is pulled out of sight. Hōzukimaru tells the others that Ikkaku is fine since his Zanpakuto is still alive. They continue onwards without Ikkaku.

A while later, the group finds the items that had gone missing from the 4th Division, including a caskt of sake belonging to Kyoraku. They find a hooded figure that tries to flee but gets trapped between Nanao and Hōzukimaru. As the figure takes off his cloak, the two interrogate him about what he has done to Ikkaku, but he does little but say he is sorry. They are suddenly interrupted by Ikkaku being sent flying down the waterway.

Just than, the real Toju emerges, revealing himself to be a tentacled monster. Hōzukimaru uses his Bankai, Ryumon Hōzukimaru, but is knocked away. With Nanao's Kido rendered ineffective as well, she askes Hanataro to use his Zanpakuto, but states that it is a healing type and that he had left it back above, not thinking he'd need it. The Toju grabs Nanao in his tenticles as Hanataro helplessly watches on. He goes over to Ikkaku to see the mysterious being stab the latter with a sword. As Ikkaku pleasures the feel it gives him, Hanataro reconizes the sword as his own Zanpakuto, Hisagomaru. As the gauge on the sword fills to the top, a large ray gun pops out of Hisagomaru's chest. A large ray beam blasts the Toju and kills him, rescuing Nanao.

The group makes it back to the surface to report the Toju's death. They also mention that Hisagomaru had been the one stealing the items from the 4th Division. According to them, Hisagomaru explained that he had been manifested by Muramasa at the start of the rebellion, but had no grudge against his master. Despite all he tried, Hisagomaru was inable to return to his bladed form. Driven by despair, he hid in the sewers, secretly salvaging items to help him cope in his new surroundings, including Hanataro's chickens. Kyoraku asks where Hisagomaru is right now, only for the setting to change back to the manifested Zanpakuto, who had gotten lost yet again.

Assault On The Rukongai
The reports state several Toju have formed a gang and are assaulting the Rukongai. Shūhei Hisagi, Izuru Kira, Tetsuzaemon Iba, and Ikkaku Madarame are sent to deal with the gang. While running through the forest, they are interrupted by an attack by Kazeshini, Hisagi's Zanpakuto. Hisagi tells the others to continue on to the Rukongai while he fights Kazeshini. As the others leave, Kira explains to Iba and Ikkaku about Kazeshini being the inner violent desires that Hisagi does his best to surpress, with Iba referring to the relationship as troublesome. After the two fight for a while, Hisagi states he will not fight his Zanpakuto again until he learns to fight honorably, leaving to join the others.

Kazeshini is shown standing over a cliff overlooking Rukongai. He is approached by Wabisuke, Haineko, and Hōzukimaru, who lecture him on why he is still trying to kill his master. Kazeshini tells them that he's only doing what he wants to do and that they can do the same for all he cares as he departs. Wabisuke mentions that Kazeshini is acting "gloomy", with Haineko rebuttling that he's a fine one to talk.

While Hisagi's group fights the Toju gang, Kazeshini continues to attack his master time after time, each effort failing. When he encounters one of the Toju in a hut, he kills it immediately. Suddenly, an infant boy is seen lying on the floor in the hut. The infant's father asks Kazeshini to watch after his son before dying of his injuries from the Toju. Kazeshini reluctantly takes the child with him. After returning to the hill top where the other Zanpakuto from earlier are, they laugh at a blood-thirsty Zanpakuto like Kazeshini for caring for such a cute looking child. Wabisuke approaches them which unsettles the child, which prompts Wabisuke to call the latter gloomy, with Haineko once again telling him that he's not one to talk. Kazeshini desparately tries to give the kid away to them, but they refuse, saying that Kazeshini told them earlier that they could do whatever they please. All three immediately leave, much to Kazeshini's annoyance.

With the other Zanpakuto gone, Kazeshini eventually warms up the the boy despite the latter constantly annoying the former with childish antics. When a woman falls under attack by another Toju, Kazeshini protects her, though unable to understand why he did so. Realizing that he can no longer watch over the infant, he gives him to the woman and tells her to flee, despite the infant crying for Kazeshini leaving him. After the final member of the gang is killed, Kazeshini decides to have an honorable fight with Hisagi. As the two clash, Kazeshini can hear the woman he saved singing a lulliby to the infant as he cries. Kazeshini is than defeated by his master, tearfully teling the child "Don't cry." Kazeshini asks Hisagi what the two of them will do after this. Hisagi answers that he will continue to protect people and that Kazeshini will help him do it. Kaeshini smirks and jokingly says that he isn't ready to help before he changes back to his Shikai form.

A New Student And A Tragic Loss Of A Friend
Back in the Human World, at Karakura High School, Chizuru Honshō is shown hitting on Orihime Inoue yet again, once again with her efforts thrwarted by Tatsuki Arisawa. As their class begins, Misato Ochi introduces a new student, Kyōko Haida. Meanwhile, there are reports on the news that high school girls have been falling victim to a mysterious illness. Believing that a Toju is involved, Ichigo and Rukia, along with Urahara, investigate but keep missing the attacker.