When Alexander and his allies launch a bold attack on the Demon King's fortress to end the war, their plan backfires as they face the unstoppable might of their foe. Despite their defeat, Alexander is reborn as the Demon King's son two years later, retaining memories from his past life. Determined to bring down the demonic realm from within, he assumes the identity of Demon Prince Zilbagias. However, blending in as a demon prince presents unforeseen challenges, putting his resolve and tactics to the ultimate test.