アケディア

Highly knowledgeable in index magic library, he can use several kind of spells. He has a body with two heads, one of which is himself and the other is some entity named Scholastica. His two-parted head is cut down by Misuzu using Doujikiri in wich Scholastica dies at her hands while Acedia is killed by Shiori afterward. His Index's name is "Anthology of Lore: Benedictus"./

Edited from url=https://en.wikipedia.org/wiki/11eyes:_Tsumi_to_Batsu_to_Aganai_no_Sh%C5%8Djo.