Conqueror’s Haki (Haoshoku Haki) is a rare form of Haki that cannot be attained through training. Only one in several million people have this ability. This type of Haki allows the user to exert their willpower over others.
It is said that whoever possesses this type of Haki has the qualities of a king.
He has shown the ability to use Haoshoku Haki when he knocked out many of the competitors in Block C without laying a finger on them, an impressive feat considering that most of the participants in the Corrida Colosseum are strong fighters.
Hancock possesses Haoshoku Haki, which she can used to knock out a weak-willed people with a massive burst. Her exact level of mastery has yet to be demonstrated.
PORTGAS D. ACE
Ace possesses Haoshoku Haki, which he initially had no conscious control over. He first demonstrated the ability at 10 years of age, when he knocked the Bluejam Pirates except for Bluejam unconscious after an outburst of rage.
He has never been seen using Haki apart from during his childhood.
His Haoshoku Haki first awakened when he was around ten years old, when being pursued again by North Blue citizens who tried to continuously torture his family in revenge, knocking them all out, thus saving him.
He possessed Haoshoku Haki, though he was never seen using it. During the Paramount War, he was on the verge of using it against some of the World Government’s executioners to protect Portgas D. Ace, but failed because of a sudden illness attack.
MONKEY D. LUFFY
Before training under Rayleigh, Luffy displayed limited to no control over his Haoshoku Haki, and did not seem to realize he had it, but used it on instinct whenever it seemed to be most needed, and could still use it even when extremely injured.
With this training, Luffy has demonstrated the ability to focus his Haoshoku Haki, knocking out a small group with a quick glare without affecting anyone else. The true extent of Luffy’s Haki is seen when he knocks out 50,000 of Hody Jones’ men. During his fight with Chinjao during the Corrida Colosseum tournament, the two unleashed a powerful wave of Haoshoku Haki when they clashed fists. This Haki has become Luffy’s specialty.
Katakuri is able to use Haoshoku Haki, as shown when he released a large burst along with Luffy’s own Haoshoku Haki in order to knock out Charlotte Flampe and her subordinates as punishment for their interruption.
Big Mom possesses Haoshoku Haki. She was first seen using it at Sanji and Pudding’s wedding to knock a man out for questioning her relationship with Mother Carmel. When her portrait of Carmel was destroyed, a distraught Big Mom unleashed her Haki, which, along with her loud screams, incapacitated most of the party guests.
Rayleigh has mastered Haoshoku Haki to the extent that he can render a specific target completely unconscious. He is able to do this without adversely affecting anybody else near the initial target. He disabled an entire hall room of hostiles with this power, save for the Kid Pirates and Heart Pirates. Rayleigh later commented that the pirates still standing were no ordinary rookies. Only very strong and determined individuals can resist from being knocked unconscious.
After saving Luffy from a Sea King, Shanks frightened it off with a single angry glare using this ability. Later, while Shanks was boarding Whitebeard’s ship for their meeting, a large number of Whitebeard’s crew (experienced men who have survived in the New World) lapsed into unconsciousness and the ship itself began to take physical damage from Shanks’s mere presence. Whitebeard’s men attributed this to his superior Haki.