The Bite

Studying Yamamoto's cracked, blackened arm, Aizen identifies the spell as Ittō Kasō, which burns the caster's own scorched body for fuel, and admits he never expected the commander to turn Wonderweiss' blast to such use. He slips from the flames only lightly burned before a Hollowfied Ichigo pounces, driving a Getsuga Tenshō that hurls him through a building and gashes his shoulder. When the wound seals itself almost at once, Ichigo assumes rapid regeneration, but Aizen scoffs at the notion that he ever truly turned Hollow, calling the effect a tool that shields its master by instinct. He then bares his chest to show the Hōgyoku lodged within it.

Praising how far Ichigo's Reiatsu has grown, Aizen insists it all followed his plan and walks through the milestones he claims to have arranged: the meeting with Rukia and clash with Uryū that woke his Shinigami powers, the duel with Renji that taught him his blade's worth, the fight with Kenpachi that laid the groundwork for Bankai, the battle with Byakuya that began his slide toward Hollowfication, the struggle with Grimmjow that gave him command of his inner Hollow, and the encounter with Ulquiorra that drew out a deeper power. Every one of those fights, he says, played out precisely as he wished.

The opening chapter of volume 46, BACK FROM BLIND. It confirms that Aizen carries the Hōgyoku inside his own body and reframes Ichigo's entire journey as Aizen's engineering. The chapter leans on flashbacks to Ichigo's past opponents and was adapted in episode 295, It's All A Trap... Engineered Bonds!