One of the greatest weapons in One Piece is Supreme King Haki. Fans know only one in a million people to possess this power, and even among them, only a handful are able to tap into its advanced form. According to Kaido, only a handful of the mightiest characters in One Piece are capable of tapping into the Supreme King Haki Infusion. Also known as Conqueror's Haki, this power, when utilized by an individual who is incredibly strong, can lead to a sky-splitting effect.