Armament Haki (Busoshoku Haki) is a form of Haki that allows the user to use their spirit to create, in essence, an invisible armor around themselves. A heavy concentration (or coating) of this Haki can be used to harden parts of one’s body, turning the area black, thus making the user denser and more formidable, and giving their attacks greater power. As demonstrated with Vergo and later Pica, it is possible for one to coat their entire body in Armament Haki.
Notably, this form of Haki can be used to injure Logia Devil Fruit users and allows the user to defend against attacks that would otherwise cause them harm.
Here’s the list about the strongest Armament Haki Users. Of course the list contains only those characters who have already shown this ability:
10 – RORONOA ZORO
Being his personal Haki specialty, Zoro has extraordinary mastery of Busoshoku Haki. During the Dressrosa Arc, it is revealed that Mihawk taught Zoro how to imbue his swords with Haki. He can imbue Busoshoku Haki into all three of his swords at once; in doing so, he managed to cut down Pica, who had already covered his entire body with the same Haki, thereby also demonstrating his supreme mastery over Haki as compared to the Donquixote top executive.
9 – CHARLOTTE CRACKER
Cracker has incredible mastery of Busoshoku Haki, which he uses to harden his sword and biscuit armor. Luffy, a highly proficient expert of Busoshoku Haki himself, described Cracker’s Busoshoku Haki as extremely tough, which can easily withstand Luffy’s Haki enhanced strikes. After imbuing his sword with Haki, Cracker was able to cut Luffy’s arm while he was fighting in Gear Fourth, further demonstrating the power of his Haki.
8 – FUJITORA
Fujitora could clash head on physically with Sabo, a Logia-class Devil Fruit user and also a proficient Busoushoku Haki user, demonstrating an extremely high level of skill in Busoshoku Haki. He could focus strong concentration of Busoshoku Haki into his sword, turning it obsidian black and making it strong enough to defend against the razor sharp threads of the Birdcage, which can slice cannonballs and buildings with great ease.
7 – MONKEY D. LUFFY
Luffy has gained an extremely high mastery of Busoshoku Haki. When his Busoshoku Haki is further compressed and focused in his Boundman and Tankman form, his Haki is fortified to the point that powerful Busoshoku masters such as Doflamingo, Cracker, and Katakuri could not fully defend against his attacks.
6 – CHARLOTTE KATAKURI
Katakuri is an extremely powerful Busoshoku Haki user, as shown when he imbued his mochi leg with it in order to bludgeon and injure Luffy. His Haki enhanced strikes are powerful enough to counter and overpower Luffy’s own Haki enhanced attacks, and he has boasted that his Busoshoku Haki is superior to Luffy’s. When his Haki is compressed and focused when performing his Zan Giri Mochi attack, Katakuri’s Haki becomes flame-shaped like Big Mom’s Haki and Luffy’s Haki when he uses Gear Fourth and the luster of it is light blue unlike Luffy’s pinkish red.
5 – SABO
Sabo has shown incredible mastery of Busoshoku Haki, which he can imbue into his arm or his pipe. His Busoshoku Haki is strong enough to shatter Burgess’s Haki infused right arm armor, as well as Diamante’s sword. His mastery of Busoushoku Haki is superior to Bastille’s, as seen when the Vice Admiral attempted to cut him down with Haki enhanced sword strikes; not only did Sabo manage to block his Same-kiri Bocho, he even managed to destroy the entire blade with relative ease.
4 – SHANKS
Shanks has mastery over Busoshoku Haki, as during the Battle of Marineford, he imbued Busoshoku Haki into his sword in order to block a magma attack from Akainu.
3 – BIG MOM
Big Mom has immense mastery of Busoshoku Haki. By hardening her arm, she could easily block Luffy’s Gear Fourth Kong Gun, a tremendous feat as Luffy’s Kong Gun is powerful enough to break through powerful Haki based defenses of highly skilled Busoshoku Haki users such as Doflamingo, Cracker and Katakuri.
2 – SILVERS RAYLEIGH
Rayleigh has an extremely high level of skill in Busoshoku Haki, allowing him to effectively bypass the powers of a Devil Fruit user and touching the “substantial body” beneath whatever protection the fruit provides as seen when he used Busoshoku Haki to kick and redirect an attack from Admiral Kizaru. Rayleigh’s immense proficiency in Busoushoku Haki allows him to use it for devastating offense.
1 – MONKEY D. GARP
He demonstrates extremely proficient skill in Busoshoku Haki, being able to injure Luffy several times, bypassing his rubber body. He could harden his fist and turned it obsidian black, allowing him to counter and even crush Chinjao’s Haki-enhanced drill shaped head 30 years ago, proving his superior mastery compared to Chinjao, who himself is a powerful expert Busoushoku Haki user in his own right. During the Battle of Marineford, he managed to punch and hurt Marco despite the latter being in his regenerative phoenix form.