What We Know
In the vast world of One Piece, the Ancient Weapons represent the pinnacle of destructive power, capable of wiping out entire islands in an instant. While we have extensive knowledge of Pluton—a massive warship hidden in Wano—and Poseidon—the Mermaid Princess Shirahoshi who can command Sea Kings—the Uranus Ancient Weapon remains the most elusive. Mentioned for the first time by King Neptune during the Fish-Man Island arc, Uranus is the third weapon alongside its counterparts. We know it dates back to the Void Century and was likely used by the Ancient Kingdom or its enemies. However, unlike the other two, its physical form and location have never been explicitly confirmed in the manga, leading to intense speculation and the development of more than one compelling Uranus theory.
Sky-Based Theories
The naming convention of the Ancient Weapons provides a significant clue for many theorists. In Greek mythology, Pluto rules the underworld (land/sea floor), Poseidon rules the seas, and Uranus represents the personification of the sky. This has led many to believe that the third weapon One Piece fans are waiting for is a sky-based power. Some fans suggest Uranus could be a legendary flying ship or a space-faring vessel from the moon, connecting to Enel’s cover story and the high-tech civilization of the Birkans. Another sky-based Uranus theory suggests the weapon is a living being, similar to Poseidon, perhaps someone with the innate ability to control the atmosphere or weather patterns from a high altitude.
Im Controls Uranus?
One of the most popular and terrifying theories involves the enigmatic ruler of the world, Imu. During the Lulusia Incident, we witnessed a shadow in the clouds followed by sixteen beams of light that completely erased the island from existence. Many fans believe this "Mother Flame" powered object is actually the Uranus Ancient Weapon. If the World Government has possessed Uranus since the Void Century, it explains their absolute dominance over the seas. This would mean that while the Ancient Kingdom had the weapons, the 20 Kings managed to seize the most powerful one—the one that strikes from the heavens. The connection between Imu and Uranus is further strengthened by the idea that "Uranus" translates to "Heaven," and Imu sits upon the Empty Throne at the center of the world, acting as a god-like figure.
Connection to Momonosuke
An alternative Uranus theory focuses on the parallel between Shirahoshi and Momonosuke. Just as Shirahoshi is Poseidon and can communicate with Sea Kings, Momonosuke has the unique ability to hear and command Zunesha, the massive elephant that carries Zou. This "Voice of All Things" application is extremely rare and specific. Some believe that the Ancient Weapons are not all objects; if Poseidon is a person, Uranus could be one as well. Since Pluton is a ship (an object) and Poseidon is a mermaid (a living being), Uranus might be the "bridge" between the two—perhaps a person who controls a massive living entity or a force of nature. Momonosuke’s role in opening the borders of Wano and his connection to the ancient world makes him a prime candidate for being or controlling the third weapon One Piece history has hidden.
Weather Weapon Theory
Given the name's association with the sky, many believe Uranus is a device or person capable of manipulating the world's weather on a global scale. This fits perfectly with the themes of One Piece, where the Grand Line's erratic weather is a constant obstacle. A weapon that can create permanent storms, change sea currents, or trigger localized lightning strikes would be the ultimate tool for controlling a world made of islands. This Uranus theory also ties back to Monkey D. Dragon; his mysterious ability to appear during storms (like in Loguetown) has led some to speculate he might have found or is searching for the Uranus Ancient Weapon to level the playing field against the World Government.
FAQ
Is Uranus a person or an object?
This is currently unknown. Poseidon is a person, and Pluton is an object. Uranus could be either, or potentially a combination of both, such as an object that requires a specific bloodline to operate.
Is the Mother Flame actually Uranus?
The Mother Flame is a power source created by Vegapunk. While Imu used it to power a flying weapon to destroy Lulusia, it is debated whether that weapon is the original Uranus Ancient Weapon or a modern recreation based on ancient blueprints.
When will Uranus be revealed?
As One Piece is in its Final Saga, the revelation of the third weapon One Piece has kept secret is expected to happen soon, likely during the final confrontation with the World Government.
