Ancient Weapons

Three instruments of catastrophic power make up the Ancient Weapons, and no two share the same form. Their titles, Pluton, Poseidon, and Uranus, come from deities, chosen for the godlike force each is said to hold. Rather than being only lifeless machines, the group includes living creatures as well. Because the World Government dreads that knowledge of them might spark another global conflict, it uses their existence as the reason to prohibit any study of the Void Century.

Pluton has not yet appeared, but it is confirmed to be an ancient warship built on Water 7 during the Void Century, capable of enormous destruction, and it now lies hidden within old Wano Country, in a cavern below the submerged Mt. Fuji. Its shipwrights preserved the blueprints as a safeguard so a second Pluton could counter the first, passing the plans down through generations until they reached Tom and later Franky, who eventually burned them rather than let Spandam seize them. Poseidon is not an object at all but a rare mermaid able to speak with the colossal Sea Kings; every few centuries a princess born to Ryugu Kingdom inherits the title, and it has now fallen to Shirahoshi, eight hundred years after the previous holder lived in the Void Century. Uranus remains almost entirely a mystery, its name being the only detail known, so whether it is a living thing or an inanimate device is unclear. The weapons saw use in the Great War of the Void Century and are largely blamed for raising the seas that shaped the current geography of the Blue Planet.

The pirate Joy Boy played a part in keeping the weapons intact so later generations might reach them, though his motives are still unexplained. Their allure has drawn many who covet that power, among them Crocodile, the agent Spandam, and the former Emperors Charlotte Linlin and Kaidou, all of whom sought to claim one or more for themselves. Even people ignorant of the lost history have been tempted, as with Vander Decken IX's fixation on Shirahoshi. In a striking irony, both Linlin and Kaidou ruled territories that unknowingly housed a weapon, since Fish-Man Island sheltered Poseidon and Wano Country concealed Pluton. Shiki once claimed that Roger had located an Ancient Weapon, and after the sudden erasure of the Lulusia Kingdom, figures including Emporio Ivankov and Vegapunk suspected such a weapon, fueled by the stolen Mother Flame, was responsible.