Reigai

This anime-only creation serves as a container for artificial souls such as Gikon and Mod Souls, which otherwise take the form of small pills while inside Soul Society, mirroring how they exist in the Human World. The Research and Development Institute relies on these bodies to test and observe their artificial souls in a tangible form before any Shinigami carries such a soul into a mission beyond Soul Society.

Left empty, a Reigai looks like a plain mannequin with almost nothing to set it apart, though a few carry hair. Once an artificial soul settles inside, the body may keep that blank look or reshape itself to match the soul, depending on what that soul is. Kagerōza Inaba worked out how to build Modified Souls that were cloned, strengthened copies of particular Shinigami, and when one of these enters a Reigai the vessel takes on that Shinigami's face and combat power. The Reigai raised for Inaba's revolt each wear a bracelet that caps the Reiatsu of the Mod Soul within. In rare instances a living soul can occupy one instead; Inaba demonstrates this against Mayuri Kurotsuchi by swallowing a Mod Soul's red pill, casting his own unharmed soul into a Reigai and pushing the wounds he had suffered onto the artificial one.

The vessels are put to use by the Shinigami and, during the Reigai Uprising, by Inaba's rebels. Counterparts appeared for nearly every captain and lieutenant serving in the Gotei 13 at that time, the exceptions being Genryūsai Shigekuni Yamamoto, Chōjirō Sasakibe, and Yachiru Kusajishi. Among the many duplicates were those of Byakuya Kuchiki, Tōshirō Hitsugaya, Suì-Fēng, Rukia Kuchiki, and Kisuke Urahara.