Mantra

Mantra (心綱 Mantora, literally meaning "Mind Rope") is a supernatural ability that can only be used by sky people. Mantra is the Skypiean equivalent to the human's Haki. It allows sky people to use otherworldly powers by tapping into their own spiritual energies.

Overview
Unlike the Blue Sea ability "Haki" which exists dormant within all people, Mantra only exists within a select few sky people whom have proven themselves to be spiritually skilled and aware enough. Mantra is the ability to manifest the power of the mind through spirtual energy in order to use other worldly abilities. Each Skypiean who has the ability to use Mantra has their own unqiue version of the power.

Luna describes the key to unlocking Mantra as being at peace with one's soul, which is why Zaiel was unable to use his Mantra until he made peace with Tenshi's death. The use of Mantra results in major fatigue on the user, but produces astronomical abilities that make it worth while, all depending on the Mantra's strength. Mantra can also be enhanced by forces other then the users mind, shown when Nobu's trademark glasses which increase his Psychic Mantra abilities.