Fortesia Neas (フォルテシア・ニース,Forutesia Nīsu?) is a nun at the Church of Alexander Mark, she wears a habit and a wimple. She is over 60 years old and someone who does not know her own age according to Linn. She is apparently a fan of The Johnnys, an Australian pub rock band from Sydney in 1982–1989 that combined country and punk musical styles. Furthermore Linn stated that Sister Fortesia is also a big fan of The Prince of Tennis, going as far as attending the Tenimyu(Prince of Tennis Musical).
Her actual first appearance is when she asked for Isumi's help to rid the church of the spirits and demons beneath it. During her absence from the church, she was impersonated by Sonia who tried to get revenge against Nagi. She later returns to the church to find it in rubbles due to the fight the happened earlier, more specifically because of Hayate's special move Hayate no Gotoku.
Fortesia is an old woman with her eyes closed. She wears a nun's outfit.