Hollowfication Containment (New Empire)

Hollowfication Containment was a long forgotten Kidō spell that was designed by the Soul King and only used by himself or those that he teaches, it is considered a forbidden Kidō spell alongside the Soul Entombment Seal spell and was used to trap someone immensely dangerous in the form of a Hollow especially if they were strong enough that no other Sealing Kidō worked on them, it appears in the New Empire series.

Trivia

 * The Hollowfication Containment has a habit of making entities known as "Perfect Hollows".