Red-Haired Shanks was known as "the man with the most overwhelming Haki on the seas"!
Aside from his personality and strength, that reputation came chiefly from his terrifying Conqueror's Haki!
It was, without question, the strongest in the world of One Piece!
Up to the point Loa had reached before crossing over, the anime had shown only Shanks's Conqueror's Haki affecting physical objects.
Many people in this world could awaken Conqueror's Haki. Chinjao had once said that in the New World, people with Conqueror's Haki and the qualities of a king were as numerous as fish in a river.
So why had none of them achieved what Shanks had? Why did so many people with Conqueror's Haki fare miserably in the New World?
The answer lay in Conqueror's Haki itself.
Unlike Armament Haki and Observation Haki, Conqueror's Haki could not be strengthened through training. Its power grew only when its wielder grew stronger.
The one difference between Shanks and ordinary wielders of Conqueror's Haki was his strength.
The power of a Yonko made his Conqueror's Haki formidable beyond measure.
Unlike the other three, Shanks was the only Yonko who was an ordinary human. He had never eaten a Devil Fruit, nor did he need to divide his attention to develop its Devil Fruit Powers.
If a ton of material fell on someone, cotton and iron would hardly have the same effect.
And besides their Devil Fruit Powers, there was another, very practical reason the other three Yonko did not focus on Conqueror's Haki.
In a fight between equals, Conqueror's Haki was pitifully weak compared with Armament Haki and Observation Haki.
After all, it grew along with its wielder's strength. It was not a trump card for defeating someone stronger, but a power that made the weak submit to the strong—the