Haki is a power that is present within every living creature in the world of One Piece. Not everyone is able to use it, and for the people that unlock through intense trauma or training, they are not guaranteed to be able to use all three types of Haki. Usually a person will specialize in one type of Haki while possibly being able to use the other two.
Every person has a limited amount of Haki, and overusing it can cause a person to stop being able to use their Haki for a short period of time.
Haki can grant many abilities as seen below:
- Accelerated Development: Haki can sometimes become stronger in combat, especially against powerful foes.
Observation Haki, also known as Kenbunshoku Haki, provides a 6th sense to the user, allowing them to sense the presence of others even if they are concealed from view or too far away to see normally. It can also provide certain other abilities beyond just enhancing the senses. The user needs to be properly calm in order for Observation Haki to work.
- Extrasensory Perception Observation Haki allows users to see the aura of other living creatures even across massive distances, and can allow blind individuals to sense the world.
- Telepathy: Users can also sense and empathize with the emotions and true nature of other beings, though this has no combat application.
- Precognition Advanced users can train their Observation Haki to the point of being able to predict the future up to at least several seconds.
Armament Haki, also known as Busoshoku Haki, allows the user to actively use their Aura as a shield and a weapon.
- Statistics Amplification Users of Armament Haki can apply an invisible layer of armor to their body which can drastically increase their defenses and their offensive power.
- Some users can extend this armor over their weapons or clothing to enhance their offense and defense further.
- Users can also apply it to ranged projectiles like arrows. Whether Armament Haki can applied to other projectiles like bullets is yet to be seen.
- Limited Non-Physical Interaction: One of the greatest advantages of Armament Haki is the ability to hit the 'true body' of anyone using elemental intangibility such as users of the Logia Devil Fruit.
- Haki does not negate the abilities associated with the Devil Fruit, but denies the advantage of being able to turn into a normally intangible substance like smoke, gas or light.
- Armament Haki has no effect on beings which have no 'true body' behind their elemental intangibility as seen when Luffy's attacks on Prometheus have no effect.
Conqueror's Haki, also known as Haoshoku Haki, is the rarest of the three types of Haki, being used by one in a million people at best.
- Empathic Manipulation: Conqueror's Haki grants users the ability to intimidate their opponent into submission; either through inducing fear into their opponent or causing them to fall unconscious. Even wild animals can be subdued and tamed through this ability.
- Depending on the level of mastery, users can selectively target a single individual or indiscriminately affects tens of thousands of individuals in a crowd.
- Strong willpower can allow a person to resist the effects of Conqueror's Haki.
- Immensely powerful Conqueror's Haki can cause some minor damage the surroundings of the user.