Leo Demonhart, who had saved humanity from the nefarious Demon King, did not receive the expected hero's welcome. Rather, the ones he had defended treated him with doubt and enmity. Ostracized and with no other place to go, Leo ventures towards the army of his once-archenemy to seek a role. Unfortunately, the army is not the same as it was previously, having been defeated by Leo. To keep his newfound position, he must motivate and train the troops to regain their former fighting prowess.