Heion Sedai no Idaten-tachi

Eight hundred years ago, demons nearly erased humanity until desperate prayers gave birth to the Idaten, fast and overwhelmingly powerful battle deities who sealed the demons away. Centuries of peace pass, leaving the current generation with no knowledge of their natural enemy beyond stories, except for Rin, who survived the ancient war and trains Hayato, Ysley, and Paula for the possibility of its return. That day arrives when the Zoble Empire succeeds in reviving demons. The new conflict is not a repeat of the old one. Demons have learned to use human society, politics, and science, while the Idaten themselves disagree sharply about the value of human life. The coming struggle has no simple rules and no side that remains entirely pure.