Index Librorum Prohibitorum, often referred to simply as Index, is a central character in the anime series 'Toaru Majutsu no Index'. She is a young nun of the Anglican Church and the primary female protagonist. Index possesses an extraordinary memory, capable of recalling 103,000 magical texts stored within her mind, which makes her a target for various magic organizations. Her role in the series is pivotal as she serves as a catalyst for many events, often relying on her strong will and determination to overcome challenges alongside her friends.