The Aizen Incident

The Aizen Incident is a term used in the English version of the series to refer to all the events that took place during the Soul Society arc, including Rukia's first encounter with Ichigo, Ichigo's period as a substitute shinigami, Rukia's capture and (unsuccessful) Execution, the Ryoka Invasion of the Soul Society, and Aizen's emergence into Hueco Mundo.

Cause and Effect

At the beginning of the series, Ichigo Kurosaki sees and confronts Rukia Kuchiki, a Shinigami, when she enters his to perform Soul Burial on a soul. During their conversation, a Hollow attacks, having tracked Ichigo back to his house. Because of Ichigo's interference with Rukia's work in his personal effort to protect his family from the Hollow, Rukia is wounded and forced to transfer her powers to him as a desperate measure to save the Kurosaki family. During the transfer, Ichigo absorbs almost all of Rukia's powers rather than taking half, as she had intended. Having her Shinigami abilities and his own immense spiritual power, Ichigo makes short work of the Hollow and Rukia leaves.

The next day, Rukia shows up in Ichigo's class, now apparently a normal human as the other students are capable of seeing her. Rukia informs Ichigo that she is using a "gigai" — an artificial body used by Shinigami when they need to recover their powers or stay in the human world for extended periods. While she recovers her abilities, Rukia insists that Ichigo take over her job, battling hollows and performing soul burials in her stead. At this time, he is only able to transform into a Shinigami when a special seal on Rukia's glove is used to "knock out" the Shinigami portion of his soul, and is dependent on Rukia to transform. Their acquisition of the modsoul Kon removes this dependency.

Ichigo's new duties set off a flurry of activity both in the human and spirit worlds. At one point, the Hollow Grand Fisher, who has evaded the Shinigami for over fifty years, comes to the human world and attempts to consume Ichigo's sisters, Karin and Yuzu. It is at this point that Ichigo finds out that Grand Fisher killed his mother and seeks revenge. Rukia tries to keep Ichigo from fighting, as she feared the Hollow was too strong, but Ichigo orders her to go with Kon and take his sisters home. She is reminded of Kaien Shiba's last fight as a fight for honor, and reluctantly follows his orders. Ichigo greatly wounds Grand Fisher, but the Hollow manages to escape.

During a duel with Uryū Ishida, a Quincy, a massive amount of Hollows, including a Menos Grande, are drawn to the human world and defeated in one form or another, mostly by Ichigo and Ishida. Chad and Orihime Inoue also have their dormant powers awakened as a result, and each defeat a hollow on their own. Ichigo's victory against the Menos draws the attention of the Soul Society, triggering the beginning of the next arc.

After drawing the attention of Soul Society, Shinigami Captain Byakuya Kuchiki and his second-in-command, Lieutenant Renji Abarai, arrive at the real world, swiftly dispatches Ichigo, who loses his Shinigami powers in the process, arrests Rukia and takes her back to Soul Society. The damage Ichigo suffers renders him a powerless human soul, while he discovers that Rukia is guilty of a felony for transferring her powers to a human and remaining in the human world for so long. Desperate to save Rukia, he undergoes intensive training with Kisuke Urahara that nearly costs him his soul, but awakens his own Shinigami abilities by doing so. After training with Urahara, he leaves for Soul Society with Urahara's mysterious feline friend Yoruichi, along with Orihime Inoue, Chad, and Uryū. Even though Rukia had told him not to go after her, he decides to not listen to her and return the favor of saving his life. With Urahara's help, Ichigo, along with Chad, Uryū, Orihime, and Yoruichi, arrive in the Soul Society to rescue Rukia.

The Ryoka Invasion

Threshold of War

Ichigo and his friends than enter the Soul Society and arrive at the Seireitei gate. Ichigo quickly defeated its gatekeeper, Jidanbō Ikkanzaka, and, upon opening the gate, Ichigo finds Captain Gin Ichimaru waiting for him on the other side. Ichimaru effortlessly repelled Ichigo and closed the gate, prompting them visit Yoruichi's friend, Kūkaku Shiba and, after some amount of training, uses her spirit cannon, launches the Ryoka, including Kukaku's brother, Ganju Shiba, towards the Seireitei and enters it. As the crew passes through the shield surrounding Sereitei, Ichigo’s inability to control his spiritual energy results in the shell exploding, separating the group. Meanwhile, a meeting of the thirteen division captains is called for Ichimaru to explain his suspicious actions, specifically on why didn't he eliminate the Ryoka when they opened the gate. Gin merely chalks it up to a mistake on his part.

Upon dispersal of the meeting, 10th Division Captain Tōshirō Hitsugaya overhears an exchange between 5th Division Captain Sōsuke Aizen and Ichimaru, which further increases his suspicions of Ichimaru's foul play; more specifically, the exchange hints that Ichimaru intends to kill Aizen. As a result, Tōshirō later warns Aizen's lieutenant, Momo Hinamori, that Aizen's life might be in danger due to Gin's subtle threat and that Gin's lieutenant Izuru Kira, her friend, might also be "tainted". The next day, Aizen's impaled body is discovered by Momo, who immediately suspects that Ichimaru is the murderer; his appearance at the crime scene shortly after the fact and carefree attitude despite the seriousness of the situation only seem to confirm this. Momo subsequently attacks Ichimaru in a rage but is intercepted by Kira. Lost in her rage, Hinamori proceeds to release her zanpakutō and fire an energy blast at Ichimaru, which harmlessly curves away from its intended target. Izuru also releases his zanpakutō in an attempt to stop her, but both are stopped and arrested by Captain Hitsugaya. After they are taken away, Hitsugaya notes that Ichimaru was preparing to kill Hinamori. Ichimaru calmly denies it, and Tōshirō threatens to kill Gin if even one drop of Momo's blood should be shed on his account.

Ichigo and Ganju encounter and fight two 11th division members, Ikkaku Madarame and Yumichika Ayasegawa respectively. Ikkaku gains an advantage by using the shikai of his zanpakutō. Ganju attempts to escape from Yumichika using a series of tricks. Ichigo eventually overpowers Ikkaku, although he is injured in the process. Ganju and Yumichika continue their fight, with Yumichika pursuing Ganju throughout Seireitei. The 11th division captain, Kenpachi Zaraki continues to search for Ichigo, but is lost, thanks to the poor directions of his lieutenant, Yachiru Kusajishi. Ganju manages to defeat Yumichika by exploding fireworks on his face. Uryū and Orihime are confronted by Jirōbō Ikkanzaka, the 4th seat of the 7th division. Uryū is easily able to destroy the projectiles he sends at them, and destroys his ability to be a Shinigami when he threatens Orihime. Meanwhile, the 12th division captain, Mayuri Kurotsuchi, dispatches squads to locate the intruders. Ichigo and Ganju attempt to escape the Shinigamis following them by using Hanatarō Yamada, a 4th division officer, as a distraction. They failed, but the Shinigami are distracted by Sado's energy blasts elsewhere, enabling them to escape. Hanatarō promises to take Ichigo and Ganju to Rukia. Kenpachi is still attempting to find Ichigo, but Yachiru's directions are leading him in the opposite direction. He then heads to Ikkaku, and stops Mayuri from attacking Ikkaku when the latter refuses to answer any questions. With Hanatarō's help, Ichigo and Ganju begin to move towards Rukia's location. However, Ichigo is then "reunited" with Renji Abarai and fights him. Eventually, Ichigo defeats Renji, after which Renji begs him to rescue Rukia, his childhood friend, upon realizing that his freind is more important than his job. Renji is taken into detention for losing, while Ichigo is healed by Hanatarō Yamada in Seireitei's sewage system. Hanatarō and Ganju carry Ichigo away as the shinigami arrive. Hanatarō begins to heal Ichigo. Renji, despite being heavily injured, is incarcerated on the orders of his captain, Byakuya Kuchiki. Meanwhile, the shinigami high command issues all-out war against the Ryoka intruders.

As Chad continues through Soul Society, he encounters members of the 8th division. He manages to defeat them all until the 8th division captain, Shunsui Kyōraku, confronts him. Meanwhile, Ichigo begins to fight Kenpachi. However, Kenpachi's spiritual energy is so great that Ichigo cannot even attack him. Although Chad is determined to win to uphold his promise to Ichigo, Shunsui easily (albeit regretfully) defeats him. Rather than kill him, Shunsui orders Chad to be incarcerated. Elsewhere, Ichigo is fleeing from Kenpachi, terrified of Kenpachi's overwhelming power. After realizing the importance of his mission, however, Ichigo finds the resolve to face him. He manages to cut Kenpachi, but becomes overconfident after learning that Kenpachi has not mastered his zanpakutō. Kenpachi then stabs him in the chest, breaking Ichigo's zanpakutō in the process. Zangetsu, the spirit of Ichigo's zanpakutō, brings Ichigo into his world. Through fighting a hollow version of himself, Ichigo realizes that Zanpakutō are more than mere tools, and that simply knowing his zanpakutō's name does not make him more powerful. Ichigo is then able to fight Kenpachi on equal footing, and as the two clash in a massive strike, Ichigo collapses. Kenpachi falls down beside Ichigo in defeat, and Yachiru takes him away for medical treatment. Yoruichi also retrieves Ichigo. Ganju and Hanatarō arrive at Rukia's cell, but Ganju becomes infuriated because he believes Rukia was the killer of his brother, Kaien Shiba. Byakuya arrives, and Ganju decides to fight him. As Ichigo awakens, Yoruichi reveals that he is actually a woman, much to Ichigo's shock and embarrassment. Afterwards, Yoruichi shows Ichigo a device that allowed her to fly, and Ichigo uses it to go save Ganju and Hanatarō.

Endgame: The Execution

Ichigo then goes to the tower where Rukia is being held to save both Hanatarō and Ganju from Byakuya Kuchiki. Upon his arrival he confronts Byakuya, even though he is not at full strength. The fight goes better than his first confrontation with Byakuya but this time Yoruichi stops the fight, knocks out Ichigo, and escape with him. As Renji Abarai recovers in his cell, the spirit of his zanpakutō, Zabimaru, says that he wishes to face Ichigo Kurosaki's zanpakutō, Zangetsu, again, but Renji tells him that Ichigo is no longer his enemy. After Ichigo regains consciousness, she begins to instruct him in the use of his bankai, the final stage of his zanpakutō that would vastly increase his power. Uryū Ishida and Orihime Inoue are attempting to travel to Rukia Kuchiki's cell by using shinigami clothes, but they are closely watched by twelfth division captain Mayuri Kurotsuchi. Uryū and Orihime continue towards Rukia's location, but are accosted by Makizō Aramaki, a shinigami of the eleventh division. Some twelfth division members arrive to help, but Captain Mayuri Kurotsuchi, who has made them into human bombs, detonates them. Orihime uses her powers to protect Uryū and herself from the explosions, and Mayuri expresses his wish to experiment on Orihime. Uryū begins to fight Mayuri, but is quickly disabled by the paralzying abilities of Mayuri's zanpakutō when his lieutenant, Nemu Kurotsuchi, uses her body to hold down Uryū. Mayuri then reveals that he has experimented on many other Quincy, including Uryū's grandfather, Sōken Ishida, and was responsible for his death. Uryū uses the Quincy technique ransōtengai to overcome the paralysis of Mayuri's zanpakutō. However, he is outclassed by Mayuri, and is forced to take off his sanrei glove, an act that releases the limits on his powers. Uryū proceeds to completely overwhelms Mayuri, but Mayuri escapes by transforming into a liquid.

Uryū continues on towards Rukia's cell, severely weakened, until he is confronted by Captain Kaname Tōsen. Kanane disables Uryū instantly with his zanpakutō, and has him incarcerated. Yoruichi summons Zangetsu using a tenshintai, one of Kisuke Urahara's inventions. Zangetsu states that if Ichigo defeats him, he will be able to perform his bankai, and will be slain if he fails. Elsewhere, Hanatarō Yamada is admonished by his captain, Retsu Unohana, for helping Ichigo, Renji breaks out of his prison cell, Captain Ichimaru releases his lieutenant, Izuru Kira, from his imprisonment, and Captain Zaraki agrees to help Orihime find Ichigo in order to fight Ichigo again.

While incarcerated, Lieutenant Momo Hinamori recalls her experiences at the Shinigami Academy, where she befriended Renji and Izuru. On a field trip to hunt hollows, she and her comrades were saved by Captain Sōsuke Aizen and the then-lieutenant Gin Ichimaru when powerful hollows attacked. Back in the present, Momo knocks her guard unconscious and escapes from her cell, planning to confront the person who killed Sōsuke. After Ichimaru releases Izuru from his cell, Toshiro becomes suspicious and confronts the lieutenant and captain together. He is interrupted by Momo, who now thinks that Toshiro murdered Sōsuke and subsequently tries to kill him. She grips her sword so tightly that her hands bleed. Toshiro then knocks Momo unconscious, acts upon his earlier threat and attacks Ichimaru, culminating in a short battle between the two. Toshiro releases his Zanpakutō and warns Izuru to get out of the way, which he, more or less, does. Toshiro and Ichimaru begin to fight, and Ichimaru initially takes the upper hand with his swordplay. Toshiro turns the tables by using the shikai of his Zanpakutō to immobilize Ichimaru by freezing his arm, causing him to open his eyes and drop his smile for the first time. Upon being trapped by Toshiro, he attempts to kill Momo as a distraction, but his attack is blocked by Lieutenant Rangiku Matsumoto, who threatens to fight him if he doesn't stop; Ichimaru withdraws and disappears without saying a word. Meanwhile, Renji arrives at Ichigo's training spot, and reveals that Rukia's execution date has been moved to the next day.

Kenpachi, along with Orihime and his subordinates, begins to travel to the execution grounds, but are confronted by captains Sajin Komamura and Kaname Tōsen and their lieutenants, Tetsuzaemon Iba and Shūhei Hisagi. Ikkaku Madarame and Yumichika Ayasegawa, Kenpachi's subordinates, begin fights with Iba and Hisagi respectively, and Komamura and Tōsen attack Kenpachi. Elsewhere, Renji has acquired his bankai, and Yoruichi is confident that Ichigo will do the same. Renji travels to Rukia's execution area, and meets his captain, Byakuya Kuchiki, along the way. Renji uses his bankai to fight Byakuya, but his lack of experience with his bankai stymies his efforts. Byakuya uses his own bankai, and defeats Renji. Kenpachi is holding his own against both Komamura and Tōsen, forcing Tōsen to use his bankai, which removes all of Kenpachi's senses with the exception of his sense of touch. Despite being unable to see Tōsen, Kenpachi manages to locate and injure Tōsen, but is stopped from killing him by Komamura. Sajin activates his bankai and engages Kenpachi.

Meanwhile, as Rukia is being led to her execution, Gin briefly appears on the bridge to tease her by giving her hope that he would stop the execution if she asked, only to admit he was lying after doing so, thus destroying Rukia's hard-built peace over her coming execution and showing just how sadistic he can be. It is at this point that Rukia mentions her fear of him. This serves only to increase suspicions that Gin was the orchestrator of her execution. Rukia has accepted her execution, and gives a request to General Shigekuni Yamamoto-Genryūsai to send Ichigo and his friends home after her execution. The sōkyoku, a massive halberd that transforms into a phoenix, is the execution method. However, Ichigo steps forward and stops the sōkyoku with his sword, and sympathetic captains Shunsui Kyōraku and Jūshirō Ukitake destroy the sōkyoku. As Renji arrives to take away Rukia, Ichigo proceeds to dispatch three lieutenants — Marechiyo Ōmaeda, Isane Kotetsu and Chōjirō Sasakibe — barehanded. He is then confronted by Byakuya Kuchiki. Byakuya begins to fight Ichigo, and promises to execute Rukia himself.

Fourth division captain Retsu Unohana personally heals all of the injured present, then leaves to investigate another location. Shunsui and Jushiro also sprint from the execution grounds, and the pair confront Yamamoto in a secluded area. In an overwhelming display, Yamamoto activates his shikai and incinerates the surrounding area. Yumichika returns to his captain after defeating Hisagi, and Kenpachi remarks that Komamura fled after Yamamoto began fighting. Shunsui and Ukitake decide to fight their teacher, and both use the shikai of their zanpakutō. Meanwhile, Soifon begins to fight Yoruichi, her former commander and teacher, and gains the advantage after she begins using her shikai. Believing she has the advantage, Soifon activates a nameless technique she recently discovered which greatly increases her power. However, Yoruichi activates the same technique, calling it "flash cry". Soifon recalls her past with Yoruichi. She was Yoruichi's personal guard, and highly faithful to her. However, when Yoruichi left Soul Society, she felt betrayed, and carried a grudge against her mentor from that point forward. As Soifon attacks, Yoruichi uses her flash cry to block all of Soifon's attacks. Soifon breaks down in tears, asking Yoruichi why she did not take her along when she left the Soul Society.

Ikkaku and Tetsuzaemon are fighting, albeit casually for sake. Near the execution site, Ichigo uses his newly learned getsuga tenshō technique to defeat Byakuya's shikai, and requests that Byakuya use his bankai. Byakuya uses his bankai and overwhelms Ichigo with millions of tiny blades. In response, Ichigo uses his own bankai, which makes him incredibly fast. Ichigo evades Byakuya's bankai and stabs him with his sword. Byakuya uses the second form of his bankai, summoning several rows of swords. As he and Ichigo continue to fight, Ichigo becomes progressively weaker as the strain from his bankai increases. Again, Hollow Ichigo takes over his body after Byakuya wounds him, and he starts to overwhelm Byakuya. However, Ichigo manages to suppress his inner hollow, and regains control over his body. Both Ichigo and Byakuya focus the remainder of their powers and clash in a final strike, with Ichigo the victor. Byakuya reveals that he wished to execute Rukia to fulfill an oath to his parents, and admits defeat, claiming that Ichigo has convinced him not to execute Rukia.

Revelation: A Madman's Ambitions

Seeing how destructive Rukia's execution is becoming, Toshiro tries to stop the execution by appealing to the Central 46 Chambers, only to discover all 46 members are dead. Kira arrives, and Toshiro and Rangiku pursue him. Toshiro returns when Izuru tells him that Momo has entered the Central 46 Chambers. Ichimaru meets Momo and takes her further into the chambers, where she is reunited with Captain Sōsuke. Aizen impales her with his sword, and Aizen and Ichimaru leave the chamber. Toshiro arrives, and is horrified at Momo's state. When Toshiro asks Aizen why he did it, Aizen replies that he was being compassionate and states that "admiration is the furthest thing from understanding". Toshiro uses his bankai, but ends up just as wounded as Momo. Captain Retsu Unohana appears, denouncing Aizen after discovering that he is a traitor. Aizen then informs her that everyone has been under the hypnosis of his zanpakutō, with the exception of the blind Kaname Tōsen, Aizen's other accomplice. At Unohana's command, Isane Kotetsu informs all high-ranking members of the Gotei 13 of Aizen's duplicity. Aizen arrives at Rukia's execution site, where Tōsen has brought Rukia and Renji. When Aizen asks Renji to leave Rukia, he refuses and begins to fight Aizen. Ichigo also arrives, and the two fight in unison against Aizen. Aizen defeats both of them, and begins to explain his reasons for betraying Soul Society until he is interrupted by Captain Sajin Komamura.

Aizen defeats Komamura with an extremely powerful kidō spell and continues his explanation. He expresses his desire for the Orb of Distortion, an artifact that would allow him to create an army of Hollow/Shinigami hybrids for his plan to overthrow the Soul Society's leader, the Soul King, usurp his power, and rule as a god. He started conducting illegal experiments on Hollows but none were able to reach his expectations. He then discovered that Kisuke Urahara had created a device called the Orb of Distortion that had the ability to create the said hybrids that exceeded his expectations and devised a plan to experiment on Urahara's comrades (The Vizard), prompting him to bring the Orb, cure them, steal it and frame Urahara for his crime. After his comrades' lives were saved by the Orb, Urahara was banished from the Soul Society for creating an object which "defied all logic within the Soul Society" along with Tessai Tsukabishi and Yoruichi Shihōin. To keep Aizen from getting the Orb, Urahara created an untraceable gigai and gave it to Rukia when she lost her Shinigami powers. Thus, Aizen extracts the Orb from Rukia, where Kisuke Urahara had hidden it. When he orders Ichimaru to kill Rukia, Byakuya saves her, taking the hit in her place. Aizen, Ichimaru, and Tōsen are then surrounded by the majority of the Gotei 13, looking to arrest/kill Aizen and his accomplices. Gin is restrained by his childhood friend, Rangiku, Tōsen is restrained by his lieutenant Shūhei Hisagi and Aizen himself is restrained by Soifon and Yoruichi. The three escape to Hueco Mundo with the help of the Menos Grande's Negación and are deemed traitors to Soul Society.

Before leaving, Gin tells Rangiku that he would have "liked to be held by her a little while longer", and unexpectedly apologizes to her (this being another rare moment where he is seen without a smile). Kaname informs Sajin that his creed in life is to "take the path with the least amount of bloodshed"; it was for this reason that he felt it necessary to follow Aizen, despite Sajin's protests. Sōsuke also tells Jūshirō that "no one has stood on the top of the world", not even the gods, but he aspires to "stand in the heavens and end the unbearable vacancy on the world's throne". Aizen then bids the Shinigami and the Ryoka farewell before he and his fellow conspirators leave the Soul Society.

Aftermath

Afterwards, as Byakuya recovers, he explains to Rukia that he married her sister, Hisana, and adopted Rukia into the Kuchiki clan due to Hisana's dying wish. However, he broke the clan's rules in doing so, and swore to his parents to uphold rules regardless of the circumstances from that point forward, and was torn between following the rules and allowing Rukia's execution or breaking them to save her. After a week-long recovery, the Ryoka finally leave the Soul Society, excluding Rukia who has decided to stay in the Soul Society even after they had tried to kill her. Prior to leaving Soul Society, Ichigo is given a badge by Ukitake that serves as a license that allows him to hunt hollows in his area officially. It is a multi-purpose artifact that functions like Rukia's glove for the task of removing souls from bodies. Unlike her glove, but similar to her Cellphone, it alerts him to the presence of Hollows.