The One Piece world is full of mysteries, and one of the biggest that Eiichiro Oda has managed to introduce in the story is that of the Ancient Weapons. Although the idea of the Ancient Weapons wasn't revealed to fans until the Alabasta arc, it was immediately made clear that these weapons carry immense power and will, at some point in the story, be an extremely important plot point.

Ever since then, the story of One Piece has slowly thrown focus on the Ancient Weapons and given the fans an idea of what the Ancient Weapons are truly about, with each passing arc bringing the fan base closer to the day when Oda reveals the truth behind these legendary items. At the same time, Oda has already established the basis for the usage of the Ancient Weapons and even explained the various types of Ancient Weapons that exist in the One Piece world.

RELATED: One Piece: Why Skypiea Is The Most Crucial Arc In The Story So Far

What The Three Ancient Weapons Are

Sir Crocodile, a former Shichibukai

The Ancient Weapons are known to be weapons of mass destruction in the One Piece world that possess power great enough to completely destroy the world. In fact, their power is such that they were named after deities, Pluton, Poseidon, and Uranus, drawing parallels to the godly power that they possess. To understand the need for the Ancient Weapons, fans needn't look further than the Void Century in the One Piece world, which obviously plays a key role in every overarching plot of the story. The prosperous Ancient Kingdom, whose name isn't known to the fans, flourished long ago and they were known to be incredibly powerful as well. However, the war against several kingdoms, the records of which have been mostly destroyed, saw a major power shift around that time.

While fans do not know what happened in this century-long void that took place 900-800 years ago, at the end of it, 20 kings established the World Government. The descendants of these kings moved to Mariejois and came to be known as the Celestial Dragons. It is believed that the Ancient Weapons were 'created' or used by the Ancient Kingdom in their war against the great enemy that they faced in the past.

RELATED: One Piece: Strong Characters That We Are Yet To See In Action

Uranus is one Ancient Weapon that fans know absolutely nothing about so far, however, the other two have been explored by Oda in some manner. The first Ancient Weapon to be introduced in the story was none other than Pluton. The weapon holds tremendous importance in the history of One Piece as it is what the Ancient Kingdom probably used to fight back against the enemy that they were faced with. Pluton is a warship said to have been built over 800 years ago on the island of Water 7. The power of this weapon is described to be such that a casual attack is strong enough to completely eradicate an island from the face of the planet. As a safety measure, Pluton's blueprints were passed down from generation to generation within the Water 7 shipwrights until they eventually reached Franky, who destroyed them after trusting in Nico Robin. Currently, the location of Pluton remains unknown.

One Piece Princess Shirahoshi Mermaid Ancient Weapons

Some arcs later, Oda introduced another Ancient Weapon to the fans, called Poseidon. Unlike Pluton, Poseidon isn't weaponry or a warship. Instead, Poseidon is a mermaid who is reborn every few centuries in the world of One Piece and it is believed that eventually, Poseidon will be guided by a special someone so that her power can be put to the right use. The identity of the previous Poseidon remains unknown, however, Shirahoshi, the daughter of King Neptune and Queen Otohime, currently possesses this power. Essentially, Shirahoshi is among the strongest characters in the One Piece world and can develop into a devastatingly destructive force.

Poseidon is known to have the power to be able to talk to and control all the Sea Kings, making her an incredible ally to whoever befriends her. The Sea Kings are extremely loyal to her and while she isn't physically strong, the power that she holds dwarfs that of even the strongest people in the world. To put into perspective how strong Shirahoshi is, fans can look at the Noah, an ark that is quite special to the Fishmen and Merfolk, all of which believe that it will eventually take them to the surface when Joy Boy returns and fulfills his promise. Noah is known to be over half the size of Fishman Island, which is quite massive itself. This Noah was easily stopped by just a few Sea Kings on Shirahoshi's command. If she wants to, she can easily sink multiple islands and destroy the entire world in the process. Shirahoshi's role as Poseidon will eventually be focused on more in the story going forward.

What Their Significance In One Piece Will Be

One Piece The mysterious frozen straw hat

The Ancient Weapons are tied to the overarching plot of One Piece and will become incredibly important in the endgame of the story. It is highly likely that Pluton will eventually be found at some point by either Monkey D. Luffy and the Straw Hat Pirates, one of their allies, or the World Government. Either way, it is bound to come into play when the Great War that the likes of Whitebeard, Oden, and Gol D. Roger knew would come finally ensues. Franky's role, although not as big as Robin's, could also be key here. Oda rarely wastes any panel in his manga, and every single plot thread has great significance. While Robin knows the location of the Pluton, Franky could have memorized how to build one, opening up the room for more than one of its kind existing in the final war.

RELATED: One Piece: How Marineford Changed The Series For The Better

Poseidon, on the other hand, will be just as important in the story, if not more. The original Poseidon was to play a key role in ordering the Sea Kings to take the Fishmen and Merfolk to the surface, where everyone would live in harmony. It is also possible that Poseidon played a role in the war, given that she was an ally of Joy Boy. Luffy, potentially being the next Joy Boy, will likely work together with Shirahoshi to finally fulfill the centuries-old promise.

In time, fans will also find out what the Ancient Weapon Uranus is, and the fact that Oda has left it for last is certainly intriguing, to say the least. Just like the other two weapons, Uranus is likely going to have the power to make or break the world of and its true potential. Thankfully, the story is finally entering its climax as the Wano Country arc barrels towards its end with each passing chapter. The mystery of Uranus and the point where the Ancient Weapon will be called into action isn't too far away now as fans inch closer to what Oda described to be a war that will dwarf the Marineford arc, one of the greatest arcs in manga history, in every way possible.

MORE: One Piece: Straw Hats Who Deserve A Higher Bounty