Aizen

Biodata

Power Progression

Background and History

Early life and the Fifth Division

Aizen grew up in Rukongai and entered the Shin’ō Spiritual Arts Academy seeking to understand the world. He encountered discrimination from noble students, graduated after six years, and joined the Fifth Division, attracted by its emphasis on teamwork 86 99 101.

Observing Soul Society’s treatment of dissenters and departing Squad members, Aizen concluded that its system kept Soul Reapers under noble control. He initially considered reform, but records in the Great Spirit Book Gallery convinced him that the existing order had to be overthrown and rebuilt. Rei intercepted him after the infiltration, but Aizen escaped using Kyōka Suigetsu 99 101 102.

Hōgyoku research and Hollowfication

Aizen collected more than ten thousand Soul Reaper soul fragments during the Seireitei Research Institute explosion. After years of experiments, he created a black substance called the Hōgyoku, intended to help him overcome his limits. It consumed soul essence to grow 108.

After sensing Rei’s power beyond the usual Soul Reaper pinnacle, Aizen began investigating Hollow power. He secretly hollowfied Seigen and later judged the controlled transformation disappointing: it raised Seigen’s Reiatsu but did not produce the evolution Aizen wanted 109 111 123.

Hirako promoted Aizen to Fifth Division vice-captain partly to keep watch over him. Aizen continued his experiments, including the Hollowfication of several Captain-level Soul Reapers. During the incident, Rei fought Aizen while Rei’s forces stole the incomplete Hōgyoku from Aizen’s laboratory 120 134 135.

Aizen later became Fifth Division captain and recruited Amagai Shūsuke by offering him power to pursue revenge against Rei. He also made another Hōgyoku using soul fragments and Soul King fragments stolen from the Tsunayashiro Clan 137 139 143.

The New World and final defeat

During the invasion of Hueco Mundo, Aizen seized the Hōgyoku from a controlled Rei. Once Rei awakened, Aizen used Kyōka Suigetsu to mislead him into a clash with Yama-jii 168.

Aizen subsequently built a base in the largest known Valley of Screams, merging other Valleys into it. He entered Hell with Tōsen, experimented with Togabito, and recruited Kūgo Ginjō and Ryūsaki Ishida into his New World organization 173 174 204 211.

While Soul Society fought the Wandenreich, Aizen began an operation to reach the Soul King Palace. He sacrificed souls to transform Tōsen and Yushima Ōshō into Ōken, then fought Ichibē Hyōsube inside the Infinite Sin Domain 240 243 246 250.

After Rei absorbed the Soul King, Aizen repeatedly revived and used his Bankai against him. Rei erased Aizen’s Ultimate Radiant Blast, made him forget his Bankai’s name, and sealed him and the Hōgyoku between life and death to supply Soul Society’s remote regions 256 257 258.

Appearance

Aizen is described as refined and gentle-faced, with an appearance that gave Amagai the impression of a scholar 139.

• Glasses: Worn during his time as Fifth Division vice-captain 123.
• Hōgyoku evolution: His later form gained a pitch-black mask and several pairs of wings ending in eyeless skulls 255.
• Black-sun form: After another evolution, a black-purple sphere floated behind him and flames of Reiatsu flickered across his clothing 257.

Personality

Aizen presents himself as approachable and composed, but keeps his distance from those who do not share his ambitions. He values knowledge and control, studying both Soul Society’s history and the habits of people who might obstruct him 99 101 123.

His hostility toward Soul Society’s hierarchy grew from a desire for reform into a determination to replace the entire order. He is also ruthless in pursuit of power: he experimented on Soul Reapers, threatened Seigen’s sister to provoke a transformation, and dissected subordinates while searching for the source of an intelligence leak 101 123 143.

Abilities & Skills

Kyōka Suigetsu

Aizen’s Zanpakutō creates illusions that distort opponents’ perceptions. He publicly described it as a flowing-water-type ability, concealing its true nature 135 147 162.

• Disguised Aizen as another person and made a piece of wood appear to Rei as a moving Aizen 103 111.
• Distorted Rei’s perception of distance and elapsed time during their battle 135.
• Caused Baraggan’s Fracción to fight one another 166.
• Continued functioning after its blade was broken, misleading Rei about Yama-jii’s position 168.
• Failed to deceive the Hōgyoku controlling Rei, which could sense wishes and see through the illusion 168.

Bankai: Kyōka Suigetsu False Life

Aizen’s Bankai negates a recently occurred reality unfavorable to him. He used it to return after an apparent defeat even when separated from the Hōgyoku 257 258.

• Rei foresaw that Aizen could use it only a limited number of additional times, even with the Hōgyoku’s support.
• It remained usable after his blade was shattered, but Rei stopped him from activating it by making him forget its name 258.

Kidō and combat

Aizen developed Captain-level proficiency in swordsmanship, hand-to-hand combat, movement, and Kidō while concealing his strength from the Fifth Division 99.

• Used Hadō #78: Zanka no Tachi against Rei and Raikōhō against Hollows 102 139.
• Bound the Hōgyoku-controlled Rei with Six-Rod Light Prison, Nine Suns Binding, and the ninety-ninth Bakudō, Forbidden 168.
• Sealed his severed-arm wound with Kidō and evaded Rei’s attacks using Shunpo 153.

Hōgyoku research

Aizen created Hōgyoku to push past the limits of a Soul Reaper and accelerate his growth. His experiments also used it to strengthen Soul Reapers and forcibly evolve Hollows 108 131.

• His incomplete Hōgyoku fell dormant for months or years after use; only ten of twenty Giant Hollows subjected to forced evolution became Adjuchas 137.
• A later Hōgyoku allowed him to withstand Ichimonji’s weakening effect and revive after Rei destroyed his body 250 256 257.
• His Ultimate Radiant Blast drew heavily on the Hōgyoku’s energy and threatened much of Soul Society, but Rei erased it 258.

Equipment and Items

• Kyōka Suigetsu — Aizen’s illusion-producing Zanpakutō 101 135.
• Original Hōgyoku — Created from Soul Reaper soul fragments; stolen by Rei’s forces while incomplete 108 135.
• Later Hōgyoku — Recreated using soul fragments and Soul King fragments; Aizen fused with it and later used it in battle against Rei 143 250 255.

Relationships

• Nangong Ling (Rei) — Rival and enemy. Aizen offered to join forces with him, but Rei refused and stole his incomplete Hōgyoku; their conflict ended with Rei sealing him 135 258.
• Shinji Hirako — Fifth Division captain who distrusted Aizen and promoted him to vice-captain to keep him close. Aizen studied Hirako’s routines to evade his scrutiny 120 123.
• Kaname Tōsen — Loyal subordinate and confidant who accompanied Aizen to Hell and later underwent the Ōken transformation 123 174 246.
• Gin Ichimaru — Aizen’s subordinate and former Fifth Division vice-captain. Aizen suspected Gin despite retaining him in his circle 137 143.
• Amagai Shūsuke — Recruited with an offer of power for revenge against Rei; he later served within Aizen’s forces 139 233.
• Kisuke Urahara — Research rival whom Aizen considered capable of creating a Hōgyoku. They later confronted each other at the Soul King Palace 136 250.
• Ryūsaki Ishida — Joined Aizen’s organization and gathered intelligence on the Wandenreich, which Aizen used in planning against Yhwach 211 219 250.

Notable Quotes

“A world order like this could only be overthrown and rebuilt.” 101

“Nangong Ling, how about we work together? With my intellect and your strength, we could completely remake the rules of the Soul Society, or perhaps even transcend them.” 135

“As expected, fear is the root of evolution!” 255