Story
The manga is set in a fantasy world where the Church of Light and the Church of Darkness have waged an unending thousand-year war, though the Church of Light seems to finally be losing. In desperation, the Church of Light magically summons a hero to their side. Though powerful, the hero is burdened with a terrible destiny: that she will die in nine days. Now the hero and her companion priestess go on their short journey as the last hope of the Church of Light.
Synopsis via AniList (English).