Haki is a mysterious power that allows the user to utilize their own spiritual energy for various purposes. All living beings in the world are capable of learning Haki; however, most people do not notice it or fail to awaken it.

Haki users are common in the New World, rare in Paradise, and basically non-existent in the Four Blues.There are three different types of Haki that can be used to sense people’s spiritual energy and predict their actions (Kenbunshoku Haki), give the user a protective coating of spiritual energy (Busoshoku Haki), and, for a certain group of “chosen ones”, overpower the willpower of others (Haoshoku Haki).

In an SBS, Eiichiro Oda, the creator of One Piece, was requested concerning the Haki users within the Straw Hat Pirates, and at that moment, there were just three.

D: “This might be out of nowhere, but who in the Straw Hat Pirates can use Haki? It’s bothering me and I can’t activate my Love Hurricane.”

Oda: “It’s these three. Their specialty haki color is in the parentheses.”

Of course this doesn’t mean that they will not power up on the other types of Haki (e.g. After pushing his Kenbunshoku Haki to its peak during his fight against Katakuri, Luffy gained the ability to see into the future to a limited extent. In addition he gained Advanced Busoshoku Haki in Wano meanwhile Zoro managed to gain conscious control over the advanced Haoshoku Haki technique infusing it into all three swords).

Simply, they’ll be Masters of each different Haki.

Zoro – Master of Busoshoku Haki

Sanji – Master of Kenbunshoku Haki

Luffy – Master of Haoshoku Haki