There are three known Haki in One Piece: Color of Observation Haki, Armament Haki, and Conqueror’s Haki. While usage of Haki itself is pretty rare, plenty of main characters in the series are experts at it. The rarest case is housing all three Haki at once.
Some of the characters who are known to use the three Haki are Luffy, Zoro, Ace, and Shanks, among others. But a One Piece theory suggests that a fourth Haki exists, and Eiichiro Oda will be keeping this a secret till the grand finale of One Piece.
Eiichiro Oda Created the Bloodline of D to Carry a Fourth Haki in One Piece
According to a fan theory, Eiichiro Oda has already formulated a fourth Haki, which will debut later in One Piece. It is a special type of Haki that has been lost to time and only shows up in the rarest of individuals. Almost like how Goku was the first Super Saiyan in a thousand years.
The Haki mainly manifests in the bloodline of D. or those who carry the Will of D. Some individuals from the clan have a special haki called Ghostly Haki. Why is it called a Ghostly Haki? Because it is activated after its user dies. This Haki holds the power to materialize dreams into the real world. However, it is a spiritual Haki which is not useful in combat.
It is this Ghostly Haki that carries the Will of D., and causes a transfer of the haki into a physical form in order to manifest the power of the user’s dreams. If a living creature containing some form of Haki comes into contact with Ghostly Haki then it ricochets off due to the clash that occurs among multiple Hakis. But this is only to absorb into the nearest potential thing with no Haki. This is, in fact, what causes Devil Fruits to occur.
Ingesting a Ghostly Haki-affected fruit allows people to receive power without any form of problem or resistance. If its receiver or user can achieve the full power of the Ghostly Haki then they can manifest their dreams. The theory states that the D. Clan are naturals at Ghostly Haki and can synchronize themselves with it more easily to awaken the power.
Why Devil Fruit Users Can’t Use Their Powers in Water
The theory also states that the reason Devil Fruit users can’t use their powers is because of the Ghostly Haki. Water or seastone consumes the Ghostly Haki. Since the Ghostly Haki is a major power that is in control of the user’s other Hakis, all of the user’s powers start to get consumed together. It is because of this weakness that Devil Fruit users are completely helpless in water.
A fourth kind of Haki would be the perfect hidden weapon for Eiichiro Oda, and if the theory is true, then it will cause momentary chaos in the fandom. Fans have been wondering whether Luffy’s Fifth Gear would be enough to battle the final enemies and whether a fourth Haki would be the best kind of boost for the straw hat.
However, the theory does have many gaps, and a lot of the elements seem disconnected. If Devil Fruits are caused by Ghost Haki then Vegapunk’s extensive research into them would be of no use. The theory also fails to explain what kind of reaction water causes with Ghostly Haki to become its major weakness.
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