Chapter Summaries

Yan Si visited Byakuya and learned that the Shiba family’s secret technique let noble Shinigami become human to have children, but at the cost of illness, lost strength, or never returning to Soul Society. He escorted Rukia to the academy, recruited Shūhei Hisagi, Izuru Kira, and Renji Abarai for the Ninth Division, then headed to Runlin An to find Hyorinmaru’s future master.

• Yan Si praised Yamagane Tetsu for managing the Ninth Division and learned that Byakuya had come looking for him.
• Byakuya explained that the Shiba family’s secret technique enabled noble families to have children by turning Shinigami into humans, with severe costs; Yan Si reassured Byakuya and Hisana that they did not need to rush.
• Yan Si agreed that Rukia should attend the academy before considering training in the Ninth Division, then escorted her to the First Academy of Spirit Arts and coached her to carry herself elegantly.
• At the academy’s opening ceremony, Yan Si spotted Renji Abarai, Izuru Kira, Shūhei Hisagi, and Momo Hinamori, while Hyorinmaru urged him to find his future master, Tōshirō Hitsugaya.
• Yan Si encouraged Shūhei Hisagi, Izuru Kira, and Renji Abarai to study hard and join the Ninth Division, then left for Runlin An to fulfill his promise to Hyorinmaru.

Yan Si found Tōshirō Hitsugaya in Runlin An and persuaded him to become his disciple after explaining that Tōshirō's powerful Reiatsu was harming Granny. Tōshirō joined the academy carrying Hyorinmaru, and Yan Si left him with the Principal to enroll before heading to the Tavern.

• Yan Si found Tōshirō at Granny's cottage and explained that Tōshirō's Reiatsu was causing the marks on her arm and could eventually kill her.
• Granny encouraged Tōshirō to accept Yan Si's offer, and Tōshirō said goodbye to her and became Yan Si's disciple.
• Yan Si gave Tōshirō Hyorinmaru, and Tōshirō entered Heart Meditation and encountered the sword's enormous silhouette on an icefield.
• Yan Si brought Tōshirō to the academy, where Momo recognized him and Rukia concluded that he must be a genius.
• The Principal examined Tōshirō's Reiatsu and agreed to enroll him, while Yan Si told him to find the Ninth Division on his own.
• Yan Si left the academy, summoned Enrakyōten, and headed toward the Tavern.

Yan Si met Hirako Shinji and Kyōraku Shunsui at a tavern, where they discussed Quincy, Soul Society politics, and Aizen’s plan to create an Ōken using a million human souls. Yan Si left for the Research and Development Bureau after learning about the threat, while Hirako and Kyōraku reflected on how Shinigami’s long lives had dulled their concern for humans.

• Yan Si promised the tavern owner he would speak to the Omaeda Family about the tavern’s scarce supplies.
• Hirako told Yan Si that the Omaeda Clan had scaled back its operations amid restrictions on the nobles.
• Kyōraku Shunsui asked whether Quincy were hiding in the shadows, and Hirako said he would investigate the Human World if Yamamoto confirmed the information.
• Hirako and Kyōraku explained that Aizen needed an Ōken and reportedly planned to sacrifice a million human souls to create one.
• Yan Si left for the Research and Development Bureau after hearing about Aizen’s plan, and Hirako and Kyōraku discussed their indifference toward human lives.

Yan Si visited the Research and Development Bureau, learned that Kurotsuchi Mayuri expected Aizen’s Soul Jade to take years to evolve, and planned to ensure Aizen made a particular choice. In Hueco Mundo, Aizen’s Soul Jade absorbed Quincy power but rejected Shinigami and Hollow power, just as Baraggan brought him a captured Vasto Lorde.

• Yan Si visited Kurotsuchi Mayuri, who said Kurayashiki Kenpachi would awaken in ten days to half a month and Aizen’s Soul Jade would need at least five years to evolve.
• Kurotsuchi Mayuri told Yan Si that the Court Security Guard Squad would go to the Human World to capture Quincy and that he planned to join the research.
• Yan Si decided that once Kurayashiki Kenpachi awoke, he would go with him to Hueco Mundo and make sure Aizen made the choice Yan Si wanted.
• Aizen added Quincy soul power to the Soul Jade, which transformed into a swirling nebula, but it did not absorb the Shinigami or Hollow soul power Kaname Tōsen offered.
• Baraggan brought Aizen a captured Vasto Lorde, while he and three Adjuchas took positions around Aizen, Kaname Tōsen, and the trembling captive.

Aizen used the Hogyoku to transform Nelliel into an Espada, and she demonstrated her new power by absorbing Baraggan’s aging aura and firing a devastating Cero. After Nelliel left to choose her palace, Aizen sent Kaname Tōsen to prepare more Soul Jade experiments and continued pondering what the Hogyoku lacked.

• Nelliel endured the Hogyoku’s soul-shattering transformation and emerged as a humanoid with a Zanpakutō.
• Aizen named Nelliel the third Espada and allowed her to protect Hollows within her own palace.
• Baraggan attacked Nelliel with his aging power, but she absorbed it and fired a Cero that pierced Las Noches toward the moon.
• Nelliel walked past Baraggan and left to choose her palace while Aizen ignored Baraggan’s protest.
• Aizen told Kaname Tōsen to prepare more Soul Jade, promising to grant him power for his pursuit of justice.
• After Kaname Tōsen left, Aizen studied the Hogyoku and wondered what it was missing.

Nelliel found Pesche and Dondochakka in the Rock Forest and invited them to join her at Las Noches. After she effortlessly defeated Nnoitra, she left with her friends, while the injured Nnoitra resolved to seek power at the palace and kill her.

• Nelliel found Pesche and Dondochakka, revealed that she had escaped Baraggan, and invited them to help look after her palace at Las Noches.
• Nnoitra emerged from hiding and attacked Nelliel, but she blocked his scythes with her sheathed Zanpakuto and remained unharmed by his Cero.
• Nelliel told Nnoitra that hope still existed, then sent him flying with a kick and departed with Pesche and Dondochakka.
• Nelliel offered other Hollows a peaceful life at Las Noches, explaining that its flowers and plants could provide spiritual energy.
• Nnoitra hid among broken rocks with severe injuries and resolved to go to Las Noches, gain power, and kill Nelliel.

Yan Si, Kuroyashiki, and Urahara Kisuke prepared to travel to Hueco Mundo to investigate Aizen, with Yan Si set to prioritize reconnaissance. After the trio left, Yamamoto wondered who could inherit Ryūjin Jakka, and Sasakibe could think of no one.

• Yan Si visited Kuroyashiki at the Research and Development Bureau and learned that Kuroyashiki's Zanpakutō had annihilated his Hollow power.
• Kuroyashiki gave his Captain's Haori to Ashido and agreed to join the current Kenpachi's division after the expedition.
• Yamamoto ordered Kuroyashiki to enter Hueco Mundo and investigate Aizen, and Yan Si volunteered to go with him.
• Yamamoto assigned Urahara Kisuke to the expedition, and Urahara presented Boundary-Breaking Orbs and Direction Needles for travel and navigation.
• Yan Si persuaded Yamamoto to allow the team until the next day to depart and said he had left Enrakyōten for Tōshirō Hitsugaya.
• Yamamoto asked Sasakibe who could inherit Ryūjin Jakka, but Sasakibe could name no suitable successor.

Yan Si visited Yoruichi before leaving for Hueco Mundo, where they shared a quiet night and discussed his chances against Aizen and the Hogyoku. He left the story preparing to face the danger ahead after spending the night with Yoruichi.

• Yan Si left Old Iron in charge of the Ninth Division and told him to ask Gin for help with urgent matters.
• Yan Si entered Yoruichi's room and found her punishing Hachi Saaya for barging in; Yoruichi released Hachi and sent her to prepare food and drinks.
• Yoruichi led Yan Si to the terrace, where they watched the moon and shared wine together.
• Yoruichi asked how confident Yan Si was about going to Hueco Mundo and placed the Hogyoku before him, but Yan Si said it would not help him surpass the Captain-General.
• Yoruichi rested against Yan Si, and he whispered that the moon was beautiful before they drew close.

Urahara Kisuke, Yan Si, and Kuroyashiki entered Hueco Mundo to target Aizen, with Kuroyashiki drawing attention while Yan Si infiltrated the Palace. Kuroyashiki fought Nnoitra Gilga, who revealed his Espada identity and released Santa Teresa, and the battle ended with Kuroyashiki poised to kill him.

• Urahara Kisuke confirmed the group had reached Hueco Mundo and assigned Kuroyashiki to cause a distraction, Yan Si to seek an opening against Aizen, and himself to scout.
• Yan Si identified Aizen's Palace, then vanished toward it while Urahara Kisuke prepared to follow and Kuroyashiki charged ahead.
• Kuroyashiki confronted Nnoitra, who refused to give his name, and cut him down after Nnoitra invited him to strike.
• Nnoitra rose with greater power, revealed himself as Espada Number 9, Nnoitra Gilga, and released Santa Teresa with six scythes.
• Kuroyashiki's Gakurai Corridor monsters swarmed Nnoitra and drained his spiritual power, while Nnoitra countered with Cero and destroyed many of them.
• More monsters emerged from the sand and tore off Nnoitra's arms and feet, and Kuroyashiki declared the fight over before raising his sword.

Kuroyashiki fought Coyote Starrk in Hueco Mundo while Yan Si entered Las Noches and met Aizen. Yan Si revealed that Squad Zero’s bones formed the Ōken, and Aizen shared his findings about emotion and Hollow evolution.

• Coyote Starrk arrived and asked Kuroyashiki to spare Nnoitra, but Kuroyashiki sent Nnoitra flying away so he could fight Starrk.
• Starrk repeatedly destroyed Kuroyashiki’s white monsters with rapid Ceros, while the two slowed their fight to stall for time after Urahara Kisuke told Kuroyashiki to do so.
• Yan Si entered Las Noches, met Nelliel, and called for Aizen, who appeared and invited him to speak privately.
• Aizen and Yan Si shared tea on a rooftop as Kaname Tōsen left to confront Urahara Kisuke, who was planting a Reishi Bomb.
• Yan Si told Aizen that the bones of every member of Squad Zero were the Ōken, and Aizen said the Espada’s extreme emotions were connected to their power and evolution.

Urahara Kisuke tried to plant surveillance devices in Las Noches but was confronted by Kaname Tōsen, who trapped him inside his Bankai and pursued him through a barrage of gadgets. An explosive wall hurled Urahara beyond the barrier, and he escaped into the shadows while Tōsen searched the palace.

• Urahara Kisuke planted Reishi Bombs in Las Noches to cover the activation of surveillance devices.
• Kaname Tōsen confronted Urahara and activated Suzumushi: Final Form-Enma Kōrogi, surrounding them with darkness.
• Urahara used Reiatsu decoys and a Reishi Concealment Garment to flee as Tōsen dismantled the bombs and pursued him.
• Urahara slowed Tōsen with explosive beads and a mud wall, but Tōsen countered the obstacles with Haien.
• Urahara threw an explosive wall that blasted both men backward and sent Urahara beyond the barrier.
• Urahara escaped into the shadows, while Tōsen released his Bankai and searched from atop a palace.

Yan Si and Aizen discussed the Hogyoku’s need for extreme emotions and Aizen’s plans to evolve, including attacking Soul Society in a few years. As Yan Si left Las Noches, he confronted Baraggan and used an illusion to make him attack empty air, then departed while Nelliel wondered what Aizen’s indifference to Baraggan meant for the other Espada.

• Aizen explained that he planned to create a hybrid child using a Soul King Fragment as one way to fuse with the Hogyoku, and to attack Soul Society as another way to provoke fear of death.
• Aizen told Yan Si that he would attack Soul Society after his latest experiments were finished, likely in a few years, and urged Yan Si to prepare.
• Baraggan confronted Yan Si as he left Las Noches, but Nelliel intervened and warned Baraggan not to attack Aizen’s guest.
• Baraggan attacked an illusion and celebrated as though he had defeated Yan Si and Nelliel, while Yan Si stood untouched and then walked away.
• Nelliel carried Pesche and Dondochakka away and wondered whether Aizen considered Baraggan—and perhaps the other Espada—expendable.

Yan Si and Urahara escaped Las Noches with Kuroyashiki after Kuroyashiki’s battle with Starrk ended when Aizen released Starrk from his Bankai’s confinement. Back at Las Noches, Aizen spared the defeated Nnoitra and used the Soul Jade to begin transforming him, leaving the Espada listening to his agonized howls.

• Yan Si met Urahara outside Las Noches, learned that Urahara’s Reishi surveillance had been repeatedly destroyed, and estimated that Aizen would attack within a few years.
• Kuroyashiki fought Starrk, whose exploding wolves and enormous Ceros challenged Kuroyashiki’s Bankai, Gakurai Corridor.
• Aizen freed Starrk from Kuroyashiki’s spatial confinement, and Yan Si and Urahara used a Boundary-Breaking Orb to pull Kuroyashiki through a rift before his Bankai could strike Las Noches.
• Aizen discussed the strength of Kuroyashiki, Chiziro Kenpachi, and Kenpachi Zaraki with Kaname Tōsen and Starrk, then ordered Kaname Tōsen to bring Nnoitra to him.
• Aizen allowed Nnoitra another chance, and Kaname Tōsen inserted the Soul Jade into Nnoitra’s hollow hole, causing his body to split and regenerate as he screamed.

At a Soul Society meeting, Yan Si warned that the Arrancars could evolve and that everyone should prepare to fight for their lives in a few years. Captain-General Yamamoto assigned preparations against Aizen, while Yan Si was sent to ask Chiziro Kenpachi about his conditions for leaving Muken.

• Kenpachi Zaraki challenged Kuroyashiki to fight during the meeting, but Captain-General Yamamoto threatened to confine him in Muken, making him stand down.
• Kuroyashiki reported that he had defeated an Espada, and Urahara Kisuke revealed that Las Noches contained hundreds of lieutenant-level Hollows and at least thirty captain-level ones.
• Yan Si explained that Arrancars might evolve beyond their Resurrección, warning the gathered captains and Court Security Guard Squad members to prepare for a dangerous future.
• Captain-General Yamamoto ordered Shiba Isshin and Ukitake Jūshirō to monitor the Human World's Reishi Concentration Point and told Kurotsuchi Mayuri to find a way to move it to Soul Society.
• Captain-General Yamamoto asked Yan Si to visit Muken and learn Chiziro Kenpachi's conditions, then declared that Soul Society and Seireitei would not fall.

Yan Si concluded that extreme emotions could trigger evolution through Soul Jade and proposed having Retsu Unohana and Kenpachi Zaraki fight to the death. Yamamoto approved the plan after Yan Si promised to supervise the fight, and Yan Si left to arrange the details while privately doubting he could suppress the evolved fighters.

• Yan Si reviewed Aizen’s theory that extreme emotions could catalyze evolution and decided to explore the idea with Soul Jade.
• Yan Si visited the First Division and explained the theory to Yamamoto and Sasakibe, warning that Soul Society needed greater strength to face Aizen.
• Yan Si proposed that Retsu Unohana and Kenpachi Zaraki fight to the death, and Yamamoto agreed that their combat could make them powerful assets.
• Yamamoto initially rejected the plan because Yan Si could not guarantee he could control the two fighters, but Yan Si offered to supervise them in Muken and claimed a fifty percent chance of suppressing them with help from the Kenpachi there.
• Yamamoto approved the plan and assigned Sasakibe to cooperate with Yan Si, who left for the Third Division while privately admitting he could not safely fight two evolved Kenpachi.

Yan Si visited Gin and Rangiku in the Third Division, told them Hueco Mundo’s forces were formidable, and gave Gin a box containing the Soul Jade with instructions not to use it hastily. He wrote a poem about Retsu Unohana and sent Rangiku to prepare it for publication, leaving Gin worried that Unohana might retaliate.

• Rangiku greeted Yan Si at the Third Division gates and brought him and Gin to the Side Hall for tea.
• Yan Si told Gin and Rangiku that Hueco Mundo had become organized and might rival Soul Society in fighting strength, and confirmed that Arrancar evolution was likely possible.
• Yan Si gave Gin a box containing the Soul Jade and told him to keep it and wait before deciding whether to use it.
• Yan Si offered Rangiku and Gin money to spend at Urahara’s General Store, then began writing a new book to replenish his income.
• Yan Si wrote a poem about Retsu Unohana, and Gin and Rangiku interpreted it as describing the end of her love.
• Yan Si told Rangiku to send the poem to the printer, dismissed Gin’s concern that Unohana might attack him, and thought that the second piece of the puzzle was nearly complete.

Yan Si taught the Academy students that fear of death could drive Shinigami to fight to survive, then examined Tōshirō Hitsugaya for early graduation. Tōshirō impressed the examiners with his tactics and Shikai, and the Principal approved his graduation.

• Yan Si asked the students what mattered on the battlefield and argued that Shinigami needed to reclaim their fear of death; Shūhei Hisagi and Izuru Kira understood his point.
• The Principal invited Yan Si to examine a student applying for early graduation and revealed that first-year Tōshirō Hitsugaya had completed his coursework in four months.
• Tōshirō used grit, close-combat tactics, and Hyorinmaru's Shikai against Yan Si, impressing the students and instructors with his skill.
• Tōshirō created an ice substitute to evade Yan Si's strike, but Yan Si countered his final attack and knocked him unconscious.
• Yan Si judged Tōshirō ready, and the Principal officially approved his graduation.

Tōshirō graduated from the Academy in less than six months and joined Yan Si’s Ninth Division, where Old Iron was tasked with teaching him division duties. Yan Si then asked Shiba Isshin about the Shiba family’s Humanization Technique as he sought ways to strengthen Soul Society against Aizen, and left planning to ask Kaien about its records.

• Yan Si brought Tōshirō to the Ninth Division, where he announced that Tōshirō had graduated and was officially joining the division.
• Old Iron was surprised by Tōshirō’s rapid graduation, and Yan Si told him to guide Tōshirō as he learned how to serve in the Ninth Division.
• Yan Si reflected that Tōshirō had graduated far sooner than expected and decided he needed someone to help solve the second piece of a puzzle.
• Yan Si asked Shiba Isshin to show him the Shiba family’s Humanization Technique, explaining that Soul Society needed to grow stronger to face Aizen.
• Shiba Isshin admitted he had secretly read the technique’s texts as a child but could not use it, and told Yan Si to ask Kaien about it.
• Yan Si left after asking whether the Human World was safe, while Shiba Isshin wondered what he was trying to do.

Yan Si trained Tōshirō and attended a captains’ meeting where Unohana challenged him to a future duel and the captains discussed the Wandenreich and Aizen. The meeting ended with Yan Si emerging as the leading candidate to succeed Yamamoto as Captain-General.

• Yan Si trained Tōshirō through the night by having him dodge silent pebbles, then told him to keep developing his strength instead of seeking a Soul Jade.
• Unohana unleashed her killing intent at the captains’ meeting after Yan Si’s novel revealed her identity as the Killer, and Yan Si agreed to fight her later in Muken.
• Urahara and Kurotsuchi reported that they had found no Wandenreich in the Dangai, while Kurotsuchi shared a Quincy hymn describing the sealed king’s return.
• Yan Si asked Kurotsuchi to release Ishida Sōken and asked Shiba Isshin to look after him in the Human World.
• Yamamoto ordered the captains to continue preparing for the Wandenreich and Aizen, while Unohana warned Yan Si not to keep her waiting for their duel.
• Hirako and the other squad members discussed Yan Si as Yamamoto’s likely successor, and a black presence stirred in the meeting room’s shadows before vanishing.

Yan Si visited Jūshirō Ukitake and the Shiba family, where he searched their old records for the Humanization Technique. He learned how the technique reunited a Shinigami’s soul with a human body and left the Shiba household after sharing a meal with them.

• Yan Si checked on Jūshirō Ukitake, reassured himself that Ukitake’s illness could not worsen, and agreed to dine with the Shiba family.
• Shiba Miyako invited Yan Si to the Shiba residence, where Koganehiko and Ginkanehiko welcomed him and Shiba Kaien, Kūkaku Shiba, and Ganju Shiba greeted him.
• Yan Si asked Kaien to search the family’s books and copied the records in the underground chamber before finding the Humanization Technique.
• Yan Si learned that the technique placed a Shinigami’s soul in a prepared human body and joined them with a Chain of Fate, which would cause aging and make separation increasingly costly.
• Yan Si returned to the Main Hall, praised Miyako’s cooking, and toasted the Shiba family with Kaien.