Haki is one of the most important powers in the One Piece world. In fact, it can be said that this power is the secondary power series, and it keeps on growing in terms of importance in the post-time skip of the story. In the final saga, Haki might just be more important than ever before, and that is because Oda keeps exploring deeper facets of this power.

Right now, it can be said that Haki has many incredible types, and the rarest of them all is only wielded by a select few who have what it takes to be extremely special in the One Piece World.

5. Advanced Grade Armament Haki

• Type: Armament Haki
• Notable Users: Nine Red Scabbards, Zoro, Hyogoro, etc

Advanced Grade Armament Haki is an ability that fans were properly introduced to in the post-timeskip of One Piece, specifically in the Wano Country arc. However, this ability was first shown to the fans right around the timeskip mark, by none other than Silvers Rayleigh. This is an incredible power that was properly explained to Luffy by none other than Hyogoro of the Flower.

Essentially, this ability is a more refined version of the regular Armament Haki. Instead of wasting Haki, it requires the power to be focused on at one point, and then is made to flow from the body. When this happens, Haki can be emitted from a distance, and it also does more damage to the enemy, which makes this power as special as it is. Luffy, with this power, thought he could break through Kaido’s scales, and this was proven by the Nine Red Scabbards being able to do just that.

4. Future Sight Observation Haki

• Haki Type: Observation Haki
• Notable Users: Luffy, Shanks, Katakuri, Kaido

The ability to take Observation Haki to the very next level is very rare. In fact, in the entirety of One Piece, only a handful of individuals have showcased the power to see the future. Observation Haki, when trained beyond its limits, allows the user to see the future itself. Of course, depending on how much of a master a particular person is of this ability, they can see more of the future.

For instance, Katakuri can see quite a bit of the future, however, Shanks can see more than 10 seconds, which is absolutely incredible. Luffy himself is quite a master of this ability, however, it appears that Shanks’s usage of this power is still better. Given that this ability is used by very few individuals, it can be said that it is one of the rarest forms of Haki in One Piece.

3. Internal Destruction Haki

• Haki Type: Armament Haki
• Notable Users: Luffy, Rayleigh, etc

Internal Destruction Haki is one of the rarest abilities that fans have seen in One Piece. Essentially, this takes advanced grade Armament Haki to the next level. When one learns how to make Haki flow from their body, they can then learn an additional step that allows them to channel their Haki directly inside the body of the enemy.

This allows them to bypass all physical defenses and deal damage from the inside. This is an incredibly dangerous power, and using this ability, even enemies with the toughest of defenses can be damaged. Luffy was able to make Kaido bleed with this type of Haki, and it has continued to evolve ever since. Rayleigh also showcased this type of Haki before the timeskip of One Piece.

2. Conqueror’s Haki Infusion

• Haki Type: Conqueror’s Haki
• Notable Users: Luffy, Kaido, Whitebeard, Roger, Shanks, etc

Quite easily, one of the rarest forms of Haki in One Piece is Conqueror’s Haki Infusion. To begin with, Conqueror’s Haki is found only in one in a million people, and, from there onwards, the ability to take it to the advanced level is even more difficult. According to Kaido, only a handful of the strongest can infuse Conqueror’s Haki but those who do, gain incredible offensive and defensive powers.

Advanced Conqueror’s Haki allows an individual to coat their body in Conqueror’s Haki and infuse it in attacks. When one does that, it takes their ability to the very next level.

1. Observation Killing

• Haki Type: Conqueror’s Haki
• Notable Users: Shanks

So far, the rarest form of Haki that fans have seen in One Piece is a subtype of Conqueror’s Haki, called Observation Killing. So far, Shanks is the only user of this Haki type. Essentially, it allows Shanks to prevent his enemies from seeing the future.

Potentially, it might also allow him to stop his enemies from using Observation Haki altogether, however, that remains unconfirmed as of now. Still, it is an impeccable ability that fans will most definitely get to see more of later down the line. For now, this Haki type remains to be the rarest in the entire series.