Maybe an ancient sage in Naruto's own world who has long - been in seclusion. This sage has knowledge of different power systems beyond just chakra. He notices Naruto's pure heart and strong will and decides to pass on his knowledge of haki to Naruto, believing that Naruto can use it for the greater good of the ninja world.
In 'naruto haki fanfic', Haki can change the Naruto universe by adding a new layer of power. For example, it can make battles more complex as characters now have to consider both chakra and Haki. It might also change the way characters interact with each other, as those with Haki could sense things differently.
Percy often uses Observation Haki to anticipate the attacks of his enemies. He can sense their movements and intentions, which gives him an edge in combat, especially against fast - moving or sneaky foes like some of the monsters in the Percy Jackson world.
Haki can completely shift the power dynamics. If a character like Ron suddenly discovers Haki, he could become a much more formidable opponent. He might be able to use it to intimidate Death Eaters or other dark wizards, adding an edge to his character that wasn't there before.
In some fanfictions, Naruto might discover haki during a particularly intense battle. Maybe when facing an enemy with an unusual power that his regular jutsu can't handle, he unknowingly taps into his latent haki ability.
An OC's Haki can be developed through intense training. Just like how Luffy and the others train in the One Piece world. They could face difficult opponents and learn from each battle, gradually strengthening their Haki. For example, if they constantly fight against Logia - type devil fruit users, their Armament Haki would improve to counter their intangible forms.
The characters included the male lead, Kaido.
One Piece: I, Kaido, Don't Want to Be Teacher Kai. Author: Land Lover. It's a light novel/derivative doujin novel with transmigration, system style, infinite style, and manga elements.
[User recommendation: Transmigration to become Kaido. In this life, I don't want to become Joey Boy's Keeper.]
Pirates? The so-called freedom was more of indulgence. In the end, it was difficult to be magnanimous.
Golden Light Curse? The Conqueror's Haki could actually be improved through cultivation!
Kaido's diary? As long as she persisted in writing in her diary, she could cultivate quickly. Silly daughter, feel your father's spirit through the diary!
Life Return + Six Treasury Immortal Thief Strengthening Physique, Drunken Dragon Eight Trigrams + Eight Gates Drunken Rampage, Thunder Eight Trigrams + Five Thunder Technique…
During the Valley of God incident, Kaido and Karp joined forces to stop the unstoppable Evil Army.
In the battle of the top, Kaido created a cloud of flames to support the sinking Marlin Fando. He faced the two Four Emperors Corps alone."You can try. Even if you have to carry justice and support Marlin Fando with one hand, I, Kaido, am still invincible in the world!"
Final Battle: Eam? Heavenly Dragon National Treasure? Ancient weapons? How could a divine dragon be afraid of mortal weapons?
Everything was settled. Kaido was ready to enjoy life, but a green-skinned guy with the word "Demon" printed on his chest suddenly appeared."Dragon God, let me regain my youth…"
I hope you will like this book.
Yes, there might be. The world of fanfiction is vast, and with the popularity of both Naruto and Kaido from different fictional universes, it's not unlikely that someone has created a crossover fanfiction where Naruto has some sort of connection to Kaido. You can search on popular fanfiction websites to find out.
I think Conqueror's Haki would suit Naruto. He has that natural leadership and strong will, just like characters in One Piece who possess Conqueror's Haki. It would be a great addition to his existing confident and determined personality.