Sousei Kishi Gaiarth

Gaiarth - a world devastated by a cataclysmic war, where pockets of humanity struggle to survive amidst the wreckage of technologies made magical by ignorance. Gaiarth - a world where artificially intelligent machines doggedly pursue their programmed imperatives: to protect, or destroy, humanity. Gaiarth - a world in which an old and terrible evil has reawakened, threatening to once again bring forth Armageddon!(Source: AniDB)