The New Captain Shūsuke Amagai arc

The Kasumiōji Crisis is the term used to refer to all the events that took place during the anime-exclusive Capatin Amagai arc.

Captain Shusuke Amagai of the 3rd Division
Shūsuke Amagai is the newly appointed captain of the 3rd Division, having come from a hollow-hunting squad most of the Gotei 13 doesn't interact with. He brings with him Makoto Kibune, whom he has appointed as the division 3rd seat. Seeing that his division is not willing to accept this new captain, Izuru Kira throws a welcoming party at Rangiku Matsumoto's suggestion. This goes horribly awry when he learns that Shūsuke can't hold his liquor, collapsing after a single drink. Things only get worse when thirty Menos Grande are detected in the dangai, and the 3rd Division is sent to destroy them. While the menos prove easy to dispatch, the entire division faces death when the dimensional cleaners, which should have been shut down, come to life. Shūsuke steps in to destroy the cleaners, and the division heads back home without incident, apart from their still-drunk captain collapsing once again.

Princess Rurichiyo's Arrival
Three new people arrive on Earth: Rurichiyo Kasumiōji, a young child who appears to be a princess; Kenzaki "Kenryū" Ryūsei, a somewhat ordinary-looking shinigami; and Enkōgawa "Enryū" Rusaburō, an extremely tall and silent shinigami. Kenryū informs Rurichiyo that their gigai have yet to arrive, and so they must wait. Ichigo and Rukia are alerted to an abnormal number of hollow sightings and set out to destroy them. During their battle, Rurichiyo wanders away from her bodyguards and finds Ichigo. As she pesters him to get food for her, her two servants appear and carry her off, leaving Ichigo to deal with the hoard of hollows in their wake. Ichigo uses his bankai to dispatch them, impressing the three. Uryū helps to clean up the rest, and explains that hollow bait was used to summon the hollows. Later that day, the three move in next door to Ichigo, though they refuse to answer any questions about their purpose. The following day they become his fellow classmates. The overly cautious behavior of Rurichiyo's bodyguards causes Ichigo to be suspicious; however, he resolves to wait for them to make the first move. That night, an assassin arrives at Rurichiyo's house, and her bodyguards leave her to Ichigo and Rukia. The assassin uses a weapon with a mirror that reflects the moonlight to stun his opponents. Ichigo uses his own sword as a mirror to turn the effect back on the assassin, then easily disarms him. Rather than be questioned, he immolates himself on Ichigo's getsuga tenshō. Kenryū reveals that Rurichiyo is the heir to the high-ranking Kasumiōji clan. The clan's caretaker, Gyōkaku Kumoi, has been assassinating members of the clan to consolidate his power, and will control the clan if Rurichiyo is killed. Unable to ask the Gotei 13 for assistance, Kenryū asks Ichigo to protect her, which he reluctantly accepts after being ordered to by Rukia.

The Tour and Kumoi's Assassins Arrive
Ichigo and Rukia take Rurichiyo around town to show her the real world. Afterwards, they have dinner at his house while Kenryū and Enryū prepare the house. They get into an argument after Ichigo tries to get Rurichiyo to eat carrots, and Ichigo accidentally reveals that they hired him as a bodyguard. Rurichiyo storms out of the house and runs off to the river, where she meets Orihime. The pair are intercepted by another assassin, this one wielding an oversized guandao which attaches to his hand. When swung, it fires energy blasts which solidify into rock walls. Kenryū and Enryū arrive shortly to rescue them, followed by Ichigo and Rukia. They again leave the assassin to Ichigo, and Ichigo again manages to defeat him. Rather than be captured, however, the assassin uses his weapon to create a rock wall, which he then collapses on himself. After the group leaves, the head assassin appears to retrieve the weapon, and the next morning Rurichiyo goes missing.

Rebuilding The 3rd Division's Trust
Shūsuke Amagai orders various menial missions and training exercises in the hope of rebuilding the trust between the division and their captain. He plans to have the division rely not only on himself, but on Izuru and Kifune as well. However, much of the focus seems to be on Kifune, making Izuru feel as if he might be replaced. Izuru comes to further distrust Kifune when they investigate the ruins of the old execution ground at the request of a fellow unseated division member, Seko Shinta. The ground gives beneath them, and all three fall into the execution pit. Furthermore, it is filled with caged hollows, who are released almost as soon as they land. Izuru and Kifune begin to dispatch the hollows, but one manages to partially absorb Shinta. While this makes Izuru hesitate, Kifune is quite willing to kill him for his lack of skill. Kira holds Kifune off, and their short exchange ends up freeing Shinta, though he is not expected to survive his injuries. Amagai arrives with backup, and it is revealed that the entire affair was deliberately set up. The next morning, Rurichiyo sneaks back into the Kasumiōji family compound.

The Kasumiōji Family Compound
Kumoi finds Rurichiyo after she sneaks back into the family compound, and tells the head assassin, Hanza Nukui, to kill her while she is unprotected. Kenryū, Enryū, Ichigo, and Rukia arrive in the compound to search for Rurichiyo, and split up. Kenryū and Enryū end up locked in a storeroom by Kumoi, Rukia is found by Kenpachi Zaraki, who discovers from her reactions that Ichigo is also there, while Ichigo actually finds Rurichiyo. However, he is constantly pursued by her guards, and loses track of her. One of the child servants attempts to kill Rurichiyo, but is stopped by Zaraki, who exposes the "child" as a disguised assassin. The assassin is quickly killed by the much stronger Zaraki. Afterwards, Rukia asks Zaraki to keep the incident secret, and he agrees, stating that he does not understand what is going on. As she and Ichigo head back to meet up with Rurichiyo, Hanza tries to frighten Ichigo by momentarily releasing his spiritual pressure, only to be surprised when Ichigo shrugs it off.

The Kasumiōji Figurehead and Hanza's First Strike
Kumoi further consolidates his power by eliminating the clan members who oppose him. In the Urahara shop, Urahara reveals that there has lately been a shortage of a certain kind of spirit particles, and wonders if it is linked to the current incident with the Kasumiōji clan. Kumoi sends Hanza and a dozen assassins to take care of Rurichiyo. Hanza takes the mirror weapon held by the first assassin with him. The dozen assassins split up into groups of four to challenge Ichigo's friends, while Hanza fights Ichigo personally. Though Ichigo is familiar with the mirror weapon and easily holds Hanza off, Hanza reveals a second ability of the weapon, using it to trap Ichigo in a pocket dimension in which he cannot move. He explains that the weapon, Saiga, evolves by feeding off the spiritual energy of those who wield, hence it is much stronger in his hands than those of his subordinates. Ichigo is freed by Yoruichi Shihōin, and she points out that his group of assassins has been defeated. The assassins once again kill themselves to prevent capture, while Hanza escapes. The next morning, Kumoi succeeds in installing Rurichiyo's fiancé as head of the clan.

Hanza's Assault
Having failed in his previous attempt to kill Rurichiyo, Hanza gathers three of his subordinates from the criminal underground and requests that they be given similar weapons. Kumoi agrees, and the four set out to kill Rurichiyo, Ichigo, and his friends. In the human world, Rurichiyo tells Ichigo about how others get in trouble for her actions, until Kenryū and Enryū became her guardians and covered for her. Sensing the arrival of Hanza and his subordinates, Ichigo and Rukia stay to protect Rurichiyo while Chad and Uryū go elsewhere to split up their attackers. Hanza targets Ichigo, wanting payback for his previous defeat, while Rukia, Chad, and Uryū each fight one of his subordinates. Rukia is approached by one of the assassins, Jinnai Doko, who is able to eat his bakkōtō to gain power and fire sword blades at her. Uryu fights Kuzuryuu, whose bakkōtō transforms him into mist. Chad fights Genba, who wields the rock-creating bakkōtō of the assassin Ichigo killed. Chad is able to overpower his opponent's wall-creating abilities with his energy blasts, but Genba manages to fuse with the walls and attack him from behind. Rukia discovers how to counter Jinnai's attacks and freezes him. He manages to break free, but is consumed by his bakkōtō. Before she can pick it up, several of Hanza's assassins retrieve it. Uryu realizes that Kuzuryuu has fused with the mist and defeats him by using Sprenger, but is injured in the explosion and collapses. Chad, after taking some hits from Genba, destroys the walls to render his opponent vulnerable. After a final clash between Chad's Left Arm of the Devil and his opponent's strongest move, Chad wins the battle.

Hanza Nukui vs Ichigo Kurosaki - Rematch
Ichigo fights Hanza and breaks his bakkōtō's mirror, but Hanza reveals another of his bakkōtō's powers, and surrounds Ichigo with the light of the shards. Ichigo is sealed within a mirror dimension which causes him to relive his childhood and his mother's death. The mirror then reflects Ichigo's guilt for not able to protect her, and the illusion of his mother tries to kill him. He is able to break free of Hanza's illusions by making peace with his mother and himself, much to Hanza's disbelief. They resume battle again with Ichigo entering his hollow mode. Hanza allows the parasitic bakkōtō to consume more of his spiritual power to fight on par with Ichigo, but is still outmatched. Hanza reveals that he and his fellow assassins once served under Rurichiyo's mother, but betrayed the family by trying to kill Rurichiyo. Despite Ichigo's attempts to stop him from using his bakkōtō, Hanza refuses to admit defeat and is consumed entirely by the parasite. Back in the Soul Society, Izuru covertly follows Kifune to the Kasumiōji compound. Rurichiyo's fiancé is ordered to be locked up in his room by Kumoi. Kuzuryuu is shown to be alive and reports to Kumoi the deaths of Hanza and his comrades. Kumoi decides he has no more use for him and has Kifune, who has just entered the room, kill him, revealing that he and Kumoi are in fact in league.

Amagai's Proposal
Amagai proposes joint training between the squads, citing the failed shutdown of the cleaners but his request is denied. That night, Izuru confronts Kibune about his entering the Kasumiōji compound, which he denies. An alarm goes off, revealing Menos inside the Seireitei. Despite Izuru's orders to stay back, the squad follows Kibune out when he decides to go after the Menos in order to improve the third squad's prestige. The different squads interfere with each other in the process of attempting to reach their foes, which they cannot see. Yamamoto reveals that he orchestrated this to test Amagai, and Amagai coordinates the squads to destroy the fake menos. As a result, his proposal is approved. Izuru notices Kibune sending a Hell Butterfly out after the battle.

Rurichiyo's Decision and The Wedding
Kumoi schedules Lurichiyo's wedding for the day after tomorrow, forcing Kenryū and Enryū to take action lest he replace her with a look-alike to secure his power. Ichigo goes to speak with Lurichiyo, who reveals that she knew about the assassins' true goal and Kumoi's connection to them, and feels guilty that Chad and Uryu were injured. She escapes into Soul Society, intending to go through with the marriage to keep Kumoi in line; however, when she arrives on the other side, her eyes have gone blank and she expresses no desire to lead. Kenryū, Enryū, Rukia and Ichigo attempt to follow them, but are unable to reach Lurichiyo, as Kenryū and Enryū have been blamed for kidnapping her. On the day of the wedding, they four enter the compound to retrieve Lurichiyo, but Soifon and many members of the second division surround them, and Lurichiyo does not respond to Ichigo calling out to her. Ichigo tries to reach out to Lurichiyo, but she recognizes neither him nor the rest. Enryū unleashes his zanpakutō, which becomes a pair of large floating fists, and destroys the building. Ichigo uses the confusion to reach Lurichiyo and reveals Kumoi's intentions to Kannogi, Lurichiyo's fiancé. Lurichiyo attacks him, revealing herself to be an impostor. Soifon prevents Ichigo from harming Kumoi and Lurichiyo by allowing them to escape. Kenryū and Enryū are apprehended, but Ichigo and Rukia manage to escape with Kannogi's help. The three hatch a plan to get past the 2nd division by pretending to take Kannogi hostage. Soifon reports this to the rest of Gotei 13, and Yamamoto orders the 2nd and 3rd divisions to lead a manhunt for Ichigo and Rukia. Soifon reveals some doubts about Kumoi's intentions to Yamamoto, but he merely takes them under consideration. Izuru voices his suspicions on Kibune's recent actions and his apparent relation to Kasumiōji family to Amagai, which Amagai views with skepticism. He tells Izuru to keep an eye on Kibune just in case.

Confusion and Amagai Confronts Ichigo
The second and third squads keep watch over the Kasumiōji compound in order to catch Ichigo. Soifon returns Kenryuu and Enryuu to the Kasumiōji clan at Yamamoto's order, and continues the search despite her reservations. It is revealed that Kumoi has captured the real Lurichiyo. Kibune visits Lurichiyo, who suggests that he is afraid of something and has an ulterior motive for working for Kumoi. Kibune is noticed by a drunken squad member, whom he quickly silences. The next morning, Renji approaches Byakuya about the search, who seems unconcerned despite the fact that Rukia is being sought after, and decides to let Renji take command of the search party by himself. Ichigo, Rukia and Shuu decide to rescue Lurichiyo, but as soon as they reach the surface, Amagai attacks Ichigo and a fierce battle begins. Shuu steps in and reveals the truth about Kumoi and the Bakkōtō, which Amagai believes. Amagai is revealed to be helping Ichigo, and is also branded a criminal. Ukutake and Kyoraku grow more suspicious about what Ichigo, Rukia and Amagai know, but Yamamoto forbids them from investigating the Kasumiōji clan. Meanwhile, Renji and Ikkaku fight with Iba and Hisagi, respectively, believing that there is some reason behind Ichigo and Rukia's actions. Kira sneaks into the Kasumiōji compound in search of Kibune. There he finds Lurichiyo being held hostage. He sends off a message to Captain Amagai, but is waylaid by a number of assassins. Though he manages to dispatch them, one escapes with Lurichiyo and Kibune appears to keep him from pursuing.

Izuru Kira vs Makoto Kibune
The squads manage to put aside their fighting and set up specified territories to patrol, but Ichigo, Amagai, Rukia and Shuu proceed through unassigned territory and, making contact with members of the third division, head for the third division stadium, Lurichiyo's last known location. Izuru begins fighting Kibune. Although Izuru initially gains the advantage by increasing Reppu's weight with Wabisuke's special ability, Kibune manages to make it fly even while heavier, and reveals that he too has a Bakkōtō. He reveals his past, where his belief that weak comrades could be sacrificed caused him to be largely ostracized in the Gotei 13, and eventually assigned to an expeditionary force due to his being unable to be placed anywhere else. He reveals that he sought power in order to gain respect. With his Bakkōtō's strength, he knocks Izuru down and prepares to finish him off. Although Izuru is nearly exhausted attempting to evade Kibune's attacks, he realizes that Kibune is relying on his Bakkōtō's strength to protect his zanpakutou from having its weight increased. He manages to make Kibune's zanpakutou heavier, enabling him to get through his defenses, and Kibune attempts to draw on more of his Bakkōtō's power, but dies the process.

Suppressing the Kasumiōji Compound
Ichigo and Amagai pursue two assassins, but learn that the Lurichiyo they are carrying is a fake, and return to the arena to hear the truth about Kibune. Renji arrives to take the Bakkōtō to Yamamoto, while Ichigo, Rukia, Amagai and Shuu head to the mansion. Yoruichi reveals the truth about the clan to Soifon and Ukitake. After hearing about the Kasumiōji clan's crimes, Yamamoto orders all squads to head to the compound. Unfortunately, Hitsugaya and Rangiku, who have not received the order, attempt to capture Ichigo's group. Amagai fights Hitsugaya and Rukia fights Rangiku while Ichigo enters the compound with Shuu. Word of the plan to invade the Kasumiōji compound reaches the 10th squad, and Hitsugaya and Rangiku stop fighting against Amagai and Rukia. Yamamoto reveals that he had suspected the clan, but because of its status as a weapons manufacturer, he could do nothing until Ichigo caused the truth to be revealed. Kumoi, angry over someone (presumebly Amagai or Yamamoto) breaking his promise to protect him, grows desperate and sends a horde of assassins, all armed with Bakkōtō, after the invading Shinigami. Ichigo, Rukia and Shuu corner Kumoi, who is using Rurichiyo as a hostage. Kumoi reveals that his plan was to take control of all of Soul Society's nobility. Amagai arrives, prevents Ichigo from rescuing Rurichiyo, kills Kumoi, then teleports to Yamamoto with Rurichiyo.

Revelation
Amagai faces down Yamamoto at his office. The mastermind of the events that plagued the Kasumiōji household was his doing. Kenryu and Enryu manage to save Lurichiyo and try to subdue Amagai, but he is too strong for them. Yamamoto demands to know why Amagai wants to do this, and the latter tells him it is all for revenge. He reveals that Yamamoto killed Amagai's father, Kisaragi Shin'etsu, as he knew about the knowledge of the Bakkōtō, and Yamamoto's involvement with the Kasumiōji clan to secretly allow them to create Bakkōtō. In order to take his revenge, he joined the Soul Reapers and rose through the ranks, waiting for his time to strike, which is now. Yamamoto unleashes his shikai against him. However Amagai uses the collected Bakkōtō "eyes" to feed his own tuning fork weapon, which is revealed to also be a Bakkōtō, albeit stronger. Using the Bakkōtō, Amagai seals Yamamoto's spiritual powers, and then unleashes his bankai, Raika Gouenkaku, against him. The fight continues until Ichigo arrives to stop Amagai. Ichigo, however, does not care if Amagai's vendetta is right or not, and berates him for selfishly manipulating virtually everyone he came across in order to achieve his goal.