Kú Li Anse

Eternal Fourth Protection is a spell used by Jibril in Materialization Shiritori. It creates a magical barrier around the users target and protects them from harm. It is stated to be the highest level sealing spell and even protected Sora and Shiro from a point blank hydrogen bomb.

The spell was invented by Shinku Nilvalen, an Elf and ancestor of Feel Nilvalen and was likely acquired by Jibril when she destroyed the old Elven capital and stole all their books.