Orsola Aquinas

A former Roman Catholic Nun. She used to be a decoder of the Original Grimoire texts and was able to decode the "Book of Law", Romanic Catholic Church's important spiritual artifact. Because of this, she was treated as a liability for the danger of leaking RCC's secrets and was ordered to be terminated. Necessarius sent Touma and company to save her and ever since that, she'd became a decoder for Necessarius. She works along side of Sherry Cromwell, and the two of them gets along somewhat in volume 9.

She usually wears a black nun's robe from her days back in Romanic Catholic Church, but as of volume 16 she changes to a plain white nun's robe of the English Anglican Church. She's got unique way of talking. According to Touma, her way of thinking resembles that of a grandmother's.