Heion Sedai no Idaten-tachi

When terrifying demons attacked and threatened to wipe out humanity some 800 years ago, everyone started praying to their individual gods in the hopes that something or someone would intervene and prevent the end of humanity. With their prayers granted, a race of deities known as the "Idaten" emerged. By employing their unwavering fortitude and strong godlike powers, the Idaten manage to vanquish the demons, preserving humanity and establishing world peace. Since they have all led peaceful lives, the younger Idaten generation knows very little about the demons at this point. The new Idaten learn under Rin, the sole surviving original Idaten from 800 years ago, how to survive in a time where they seem to have outlived their utility. The oddball warriors are abruptly summoned back to confront their natural foe when the oppressive Zoble Empire revives a monster.