The mystery of Conqueror's Haki needs a whole new explanation due to a major One Piece character.
Oda Reveals One Piece's BIGGEST SECRET! HAKI is not what we thought it was! (One Piece 1122)
The power scale of One Piece is measured in two different aspects. One is the strength of Devil Fruits, and the other is the ability to use different types of Haki. In terms of Haki, nothing compares to the Color of the Supreme King, also known as Conqueror's Haki, and it is currently the strongest ability in the series.
As the series has reached its final saga, the race for the One Piece treasure has washed out all the unworthy pirates. The only ones left are those who either have the Supreme King's color or can stand up to this mysterious ability. Although no one knows its origin or how it works, the most possible explanation for the Conqueror's Haki was given by a One Piece theory that correlates it with death.
According to the theory, the only characters who can unlock Conqueror's Haki are those who can beat death. There has been several pieces of evidence to support this theory, except for one, which actually contradicts it. This aspect involves Jinbe and his brave confrontation with Big Mom, where he beat death but was unable to unlock the Conqueror's Haki.
