百野 栞

She is a "traditional magician" and is/ usually seen with a book. She seemed indifferent to the students who approached her in class at first but eventually warmed up to Kaori and Tadashi and grew to treasure them due to their friendly spirit. Her secret identity is that of an apostle of Index, the largest magical organization within the world of 11eyes and 3days. Her real name given by Index is "Anthology of Lore: Ursula". She transferred to Kakeru's school to monitor the place and report its situation to Index. Her assignment was due to the sudden disappearance of the last warden. She is extremely powerful and is a candidate for the next 14 saints, the highest officials within Index./

From url=http://en.wikipedia.org/wiki/11eyes:_Tsumi_to_Batsu_to_Aganai_no_Sh%C5%8Djo.