Restarting the End of the World: I Face Off Against the Industrial Devil

In the final battle, Rene kills the Demon King with his own hands, but triggers the forbidden magic of the Gods and the world collapses. After his rebirth, he returned to the academy to decipher the magic of the Gods and rewrite modern spells. However—— The Demon King is also reborn? Moreover, the Demon King has begun industrialization? The magic of the Gods, modern magic, and steel war are launched at the same time. This time. Rene must end the war before the world does.