Haki

Spirit Energy (覇気, Haki)

A strange technique that seems to frighten anyone just by looking in their eyes. While eye contact appears to be unnecessary, the locking of eyes seems crucial in order to centralize the effects. A powerful user, when using this technique, could render a large group of people (provided they are deemed as foes) to immediately lose consciousness, even without locking eyes with each and everyone of them, after getting within a certain proximity from where the user stands. However the reason they lose consciousness is because they are simply not ready (determined) to face against the Spirit Energy. Shanks, Silvers Rayleigh, and Luffy possess this technique, with the latter only recently exhibiting it.

Originally seen in the first chapter, Shanks used it against the Lord of the Coast in an attempt to save a young Luffy from the wrath of the sea beast, even at the cost of one of his arms. The Sea King was forced to flee with fear from this power. In Chapter 434, when Shanks went into Whitebeard's ship, he made the lesser crew members on Whitebeard's ship fall to the ground unconscious. When he clashes with Whitebeard's spear to sword, the energy split the clouds apart. Later, Luffy unintentionally uses it on Motobaro, scaring it away in a fashion oddly similar to Shanks' scaring of the Lord of the Coast, eventually causing it to faint. The latest use was by the coating mechanic that the Strawhats are looking for, Silvers Rayleigh and his display was more powerful than the one exhibited by Luffy to crush an entire audience of people at a slavery auction house.