Holy Armor of Doom: the Demon God Awakens

When the doomsday virus is raging, the countdown to the ancient demon god's awakening begins. The teenagers who bear their own destiny awaken the power of their blood in the ruins, wear the wind spirit armor left over from ancient times, and with the help of the elven allies, they face the Seven Deadly Sins demon envoys and the demon god in the last holy city of Telles, only to find that this war is just a part of the eternal cycle...