Cross-Dressing Villainess Cecilia Sylvie, Vol. 4 (light novel) — Hiroro Akizakura

Lauded for her acts of bravery during Advent Day, Cecilia (still pretending to be Cecil) is invited to the seat of the Church of Caritade for an audience with the Holy Maiden herself! There, she seizes the opportunity to procure the sacred dagger that will allow her to rid the world of Obstructions for good...only to discover that the game's major villain has made off with it first. But as she works to track the perpetrator down, Cecilia finally learns that her fiancé Oscar has seen through her disguise! Can this reincarnated villainess make it through her most harrowing predicament yet?