Sei Michaela Gakuen Hyouryuuki

聖ミカエラ学園漂流記

Reborn as a woman named Aiko, the soldier rises as the military leader of a new crusade, successfully unites the world and abolishes all religion. Haunted by memories of a past life, Aiko travels backwards in time, and finds herself caught in an incredible battle to save the future. (Source: ANN)