Sins of the Sisters

1212 AD. During the crusades, an innocent soldier finds himself betrayed, and leaps to his death, vowing to return as a fallen angel. Present day. 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. (myanimelist.net)