In the chaotic and war-torn North Blue, the small ancient kingdom of Noxas faces imminent destruction. With the old king dead and the tyrannical Germa Kingdom demanding three billion berries in fraudulent research funds, the young Prince Locke stands as the last line of defense. Refusing to flee or surrender, the fifteen-year-old prodigy relies on a terrifying secret: a monstrous physique forged by cruel training and a transmigrator's cheat ability.

While his palace crawls with spies sent by greedy nations, Locke prepares for war in the shadows. He consumes five mysterious Devil Fruits in a single night, not for their individual powers, but to unlock his true arsenal. Within his mind floats a collection of forty-eight legendary Imperial Arms, weapons of mass destruction capable of leveling nations.

As the Germa fleet approaches, Locke must decide how to wield this overwhelming power to protect his people and carve his name into the history of the greatest pirate era, potentially aligning with the infamous Rocks D. Xebec.