A young man is reincarnated as the son of a murdered King. Armed with his modern knowledge, he establishes a Spartan-inspired military regime, fusing magic and technology to create a formidable army. Faced with neighboring kingdom attempting to crush him, he wages a ruthless campaign of conquest, eliminating his enemies without mercy. Just as the kingdom and empire family begin to see him as a threat, an even darker force—the Demon Empire—emerges from the shadows. Its goal is clear: dominate or perish.