Pastor Sicilia is a member of Faust, the church organization responsible for the summoning and elimination of Lost Ones. She operates as a pastor in the port town of Libelle, where she becomes involved in an investigation into the illegal drug trade of a substance called monstrine. In this capacity, her path crosses with the executioner Menou, whom she assists during Menou's mission concerning the Lost One Akari Tokito. There is an indication that Sicilia possesses some knowledge of or connection to the high-ranking executioner Flare.