Orsola Aquinas

Ursula Aquinas is a former Roman Catholic Nun introduced in Volume 7. She used to be a decoder of the Original Grimoire texts and was able to decode "The Book of the Law", the Roman Catholic Church's important spiritual artifact. Because of this, she was treated as a liability for the danger of leaking said faction's secrets and was ordered to be terminated. Necessarius sent Touma and company to save her, and ever since then, she became a decoder for Necessarius. She works alongside Sherry Cromwell, and the two of them get along somewhat in Volume 9.

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