The Forbidden Research...Nozomi's Hidden Secret!

Mayuri corners a cornered Inaba, revealing that he swapped places with his own Reigai copy while hiding in the Dangai. When Inaba dismisses the threat of Ashisogi Jizo's paralysis, Mayuri simply stabs him, then explains he laced his first strike with a drug that dulls human thought, so Inaba could not react to a plain attack he was busy overanalyzing. Left unable to draw on his knowledge, Inaba is saved and healed by a Reigai of Isane, whom he coldly kills before swallowing a Mod-Soul pill to escape into a fresh body.

At the Urahara Shop, Ichigo wakes confused about surviving the Kototsu and wonders who rescued him. Urahara lays out Inaba's obsession: the traitor hid Mod-Soul research inside the Dangai as special Reishi and spent ages recovering it from the Cleaner. Rukia describes the abandoned Spearhead project, which sought to build enhanced fighters from soulless corpses, while Urahara recounts finding Mod-Soul data fragments clinging to Ichigo's Reishi after the rescue.

Inaba boasts that he alone perfected the Mod-Souls, incubating them with pieces of a Shinigami's Reishi to inherit their minds and amplify their abilities, and that he buried the data out of contempt for Soul Society scrapping the project. Kon fears Nozomi distrusted him for being a Mod-Soul, but she denies it, revealing that Inaba did not create Kon. Inaba then shatters his Reigai's limiters, flooding the battlefield with restored and revived copies that overwhelm the captains, as Nozomi confesses she was the very first Mod-Soul ever developed.

Mayuri incapacitates Inaba's mind with a thought-inhibiting drug. Inaba kills a Reigai-Isane and flees into a Mod-Soul body. Urahara explains that Inaba concealed Mod-Soul research inside the Dangai and used it to create the captain Reigai. Inaba releases his Reigai's full power to swamp the Gotei 13, and Nozomi reveals herself as the first Mod-Soul.

This anime-only entry has no source chapters and belongs to the Gotei 13 Invading Army arc. Its Illustrated Picture Book shows Sui-Feng recounting a dramatic rescue by Yoruichi, only to snap at Isane for pointing out that she was present too.