Ouko Yushima is the creator of Reigai and Modified Souls.
Ouko was the lead scientist in charge of Project Spearhead, an initiative in which Soul Society experimented with creating artificial souls known as Modified Souls and implanting them into shinigami corpses for the purpose of increasing the fighting capabilities of the Gotei 13. Ouko's research and experimentation eventually led him to not only copying the mental characteristics of captains and implanting them into corpses, but to enhance their abilities as well. Fearing that this gave Ouko far too much power, Central 46 ordered for the project to be discontinued and all research destroyed under the guise of it violating ethics. Rather than see his hard work destroyed, Ouko copied his findings and hid them in the Precipice World to be retrieved and continued at a later date. Hoping to avoid capture and permanent imprisonment, he split his soul in two and placed it into two modified souls: Nozomi Kujo and Kageroza Inaba. Having integrated himself into Soul Society, Kageroza devotes his time to retrieving Ouko's hidden data, overthrowing the Gotei 13, and retrieving Nozomi, who has fled from Kageroza because she disagrees with Kageroza/Ouko's plan.
Ouko is a supporting character from the anime series BLEACH, created by Tite Kubo. He is the primary villain of the Reigai Invasion arc. He is an anime-only character who first appeared in BLEACH Episode 321 "Showdown of Mutual Self: Ikkaku vs Ikkaku". His character in the Japanese series is voiced by Hiroaki Miura, who makes his first vocal appearance in BLEACH Episode 338 "Kon's Thoughts, Nozomi's Thoughts".
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