Observation Haki also known as Mantra (literally meaning "Mind Rope") on Skypiea, is a form of Haki that allows the user to sense the presence of others, even if they are concealed from view or too far to see naturally.
- Users: Various Users
- Fighting Style Focus: Presence detection, Limited precognition
It was first introduced under the name Mantra when Satori used it to fight Sanji, Luffy, and Usopp as they went through the Ordeal of Balls. Aisa is the only known Shandian who has this ability. It served as a plot point when she helped Luffy locate Eneru. It varied in strength between users, with Eneru's seemingly being the strongest. With his Devil Fruit, the Rumble-Rumble Fruit, Eneru could pick up electromagnetic waves, allowing him to overhear conversations and everything around him; this extended the range of his Mantra to cover roughly all of Skypiea. By comparison, most of the other priests could only keep track of people nearby. The first time it was seen being used and referred to as Haki was during Luffy's battle on Amazon Lily with the Boa Sisters. Later, Rayleigh explained Haki to Luffy and confirmed that "Mantra" is the Skypiean name for the ability.
The most common usage of this Haki allows the user to sense the presence of others. Rayleigh states that to fully master this ability would allow the user to see others even if they are concealed from view or too far to see naturally. When viewed this way, the user can't actually see the person with any physical characteristics, but rather recognizes the target(s) by their "aura" which forms as a light silhouette on a dark background, as demonstrated to how the blind Issho sees the world.
The user can also use this Haki to predict an opponent's moves shortly before they make them, thereby making the attack much easier to evade with enough skill. This prediction appears to the user as an image or brief "premonition" of what the opponent will do in the user's mind's eye, and the damage the user will take if the attack actually "hits". It appears that the more killing intent the enemy has, the easier they are to predict. Although, more skilled users can predict future moves whether there are ambient murderous intents or not.
This type of Haki can also allow the user to sense and empathise with the emotions and nature of others. For example, Otohime used this Haki to sense the sufferings and emotions in the heart of a Fishman thief as well as hear the screams coming from Fisher Tiger's heart. Another example is that Aisa was able to sense Wiper's aggressive nature with this Haki.
It is possible that this form of Haki allows the user to sense the strength of others as well. This was alluded to when Rayleigh used this Haki to sense that there were 500 creatures on Rusukaina who were stronger than Luffy at that time.
Observation Haki, unlike the other types of Haki, has hardly any visible indication when being used (like the blackening effect of hardening for Armament or the ripple effect for Conqueror's), aside from their enhanced dodge rate. In some instances, the user's pupils turn red when activating Observation Haki.
Though the power allows the user to predict most attacks, it can be circumvented by various means. It cannot predict inherently random attacks; for example, Luffy managed to bypass Eneru's Mantra by bouncing his fists off a nearby wall, to prevent himself and thus Enery from knowing where they would land. In the unique circumstance of being swallowed by a larger creature and still being alive, the Mantra user will only be able to sense the larger energy signature. This was shown when Eneru failed to discern the presence of Luffy inside the giant snake Nola, only detecting him after he escaped, indicating that her 'voice' most likely enveloped their own when he used the ability. Similarly, Aisa could not detect how the battle was progressing with her Mantra while inside Nola and only found out what happened after she and Luffy escaped. It also does not make the user any faster than normal, so the user's ability to dodge is dependent on their speed; Enel was unable to avoid Luffy's finishing move because it was moving too fast, even though he was able to predict it. Likewise, Luffy's Second Gear was able to outpace Boa Sandersonia, despite her ability to read his moves. It also seems to falter if the user loses their concentration. Satori lost the control of his Mantra when Luffy unexpectedly brought the string of exploding balls right to him, enabling Luffy to grab him from behind when the smoke cleared, Gedatsu lost to Chopper because he lost his concentration and his Mantra faltered, and Otohime was killed by a gunshot in the confusion when her petition pages were being burned, as she was caught off guard due to her happiness over everyone signing her petitions, she lost her concentration.
Known Observation Haki Users
- The concept of Observation Haki, known to Skypieans as Mantra, is loosely based on the style of thinking in Hinduism, which goes by the same name.