Orsola Aquinas

Orsola Aquinas (オルソラ＝アクィナス) is a nun in training who specializes in decoding magical texts. She was a member of a the Roman Catholic Church and have done many great deeds under it's name, as such she was well celebrated for it, and even had a church in Japan built for her.

She later defects to the Anglican Church after the events of the 7th Novel.

Appearance
She has slightly short blond hair and blue eyes. She initially wears a black nun's robe from her days back in the Roman Catholic Church, but as of Volume 16, her attire changes to a plain white nun's robe of the English Anglican Church.

Personality
She has a unique way of talking; according to Touma, her way of thinking resembles that of a grandmother. She often ends up talking about something unrelated before jumping back to the original topic, often leaving people flabbergasted. In Volume 11, she states that her hometown is in Chioggia, Italy.

Orsola Aquinas Rescue Arc
A former decoder of grimoires and other magical texts, she is allegedly able to decode "The Book of the Law", a powerful Roman Catholic Church grimoire. Because of this, she is captured along with The Book of the Law by the Amakusa Catholics. The Roman Catholic church sends the Anieze Forces to save her, while Necessarius sends Stiyl, who drags Index and Touma with him.

It is later revealed the the Amakusa Catholics were actually trying to save Orsola, and that the Anieze Forces were sent to dispose of her because the Roman Catholic Church labeled her as dangerous due to her being able to decode The Book of the Law. She is saved by Touma and company, and becomes a decoder for the Anglican Church. She works alongside Sherry Cromwell, and the two of them get along somehow.

Daihasei Festival Arc
When Stiyl is talking over the phone with Sherry Cromwell, Orsola is heard over the phone working along with Sherry on decoding information on the Croce di Pietro. Sherry at this point doesn't quite get along well with Orsola due to the difference in their personality, and admonished her there is no time to eat right now while working. Orsola replies this is a muffin made by the Amakusa that helps with physical recovery as she is still hurt from the events of the Book of the Law. Sherry grudging accepts that reason before getting agitated about Orsola leaving crumbs while she's eating. the phone cuts off here after some scuffling.

Later, Orsola tries to call Stiyl to report in the information found but dialled to Motoharu's phone instead by accident. Motoharu and Touma are exasperated by her thought patterns, going from greetings to a good sushi shop near Waterloo Station, before finally telling them the requirements to activate the Croce di Pietro.

Trivia

 * According to the interview on Kazuma Kamachi featured in "Toaru Majutsu no Index no Subete", Orsola is the one whom he want to choose as his wife among all Index characters.