Black Fang (くろいきば, Kuroi Kiba?), also known as Bl.Fang, Black Fangs, and Demolish, is a recurring ability in the series. It is generally associated with Golbez or the Shadow Dragon, and usually inflicts Instant Death or otherwise a powerful effect.
IV Black Fang is an enemy ability used by Shadow Dragon in a cutscene, which inflicts Instant Death to all party members but Cecil (and Kain in earlier versions of the game, if Jump is timed correctly) with 100% accuracy. This is the only time in the game the ability is ever used.
FFIVTAY Black Fang returns as an enemy ability used by Shadow Dragon as well as the Curse Dragon and Ebony Dragon, and once again inflicts Instant Death with 100% accuracy. The Dark Knight is also able to use Black Fang, which saps the HP of a party member to 1.
Dissidia Black Fang is an EX Mode only ability used by Golbez, used by holding both and . It has an extremely long charge time, but if it connects will instantly inflict Break regardless if the opponent's Bravery is locked or not, and can only be prevented through the usage of Phoenix.
Dissidia012 Black Fang returns as an EX Mode only ability used by Golbez, and retains all the properties from the previous game.
FFRK Black Fang is unique Soul Break available to Golbez which at the expense of one Soul Gauge segment deals four non-elemental magic attacks to a single target. He can use it via axe Rune Axe (IV) from which it can be mastered so it can be used without needing to be equipped with the said weapon.