"If we inject a small amount of Hollow energy into a Shinigami's soul, thus causing their Bankai to undergo a temporary "Hollowfication", even if only for a moment... That Bankai will become poison to any Quincy." |
The Shin'eiyaku (侵影薬, Shadow-Raiding Drugs; Viz "Shadow Infiltration Pills") is a pill designed by Kisuke Urahara to help Shinigami who have lost their Bankai to the Quincy's Medallions.
Overview[]
A Shin'eiyaku pill being absorbed by Hitsugaya.
By temporarily causing the user of a Bankai to Hollowfy, it effectively makes the Bankai "poison" for a Quincy due to their inability to take in Hollow Reiatsu without their souls being destroyed in the process. The pills are taken through any means of physical contact, at which point they will evaporate as their properties are absorbed by the Shinigami in question.[1] The effects were first seen when Tōshirō Hitsugaya's stolen Bankai, Daiguren Hyōrinmaru, broke and suddenly injured Cang Du.[2] The Bankai then gradually returns to the Shinigami owner, with an additional effect of the Shinigami being Hollowfied, such as Hitsugaya briefly gaining a mask of ice over his left eye and having an echoing voice.[3][4]