Iainuki

Iai Strike (居合い斬り), also known as Iai Blow and Iainuki, is a recurring Command Ability in the Final Fantasy series, and has also appeared as an enemy attack. It typically attempts to instantly dispatch the target. The job class Samurai are most often associated with the technique.

Final Fantasy V
Iainuki is the Level 5 ability of the Samurai. It has a chance to instantly kill all enemies.

Final Fantasy VIII
Iai Blow is an enemy ability used by Forbidden when it has less than 85% of its HP remaining. It does physical damage and has a chance to instantly kill the target.

Final Fantasy IX
Iai Strike is a Sword Arts for Steiner. It attempts to instantly kill an enemy. It has 30% accuracy due to a glitch.

Final Fantasy Tactics A2: Grimoire of the Rift
Iai Blow is part of the Flair skillset usable by the Parivir class. It attacks a target for damage equal to half a normal attack and has a chance to kill them instantly.

Dissidia Final Fantasy
Iai Strike is the Japanese name of one of Sephiroth's Brave attacks. It is called Sudden Cruelty in the English release. It is also an ability connected to the Smiting Soul accessory. This Iai Strike gives the user a 2% chance to inflict an instant Break on the opponent whenever they damage the opponent's Brave.

Iainuki is the ability of the Samurai card in the Duel Colosseum. When used, the Samurai card discards all Chaos and Boss cards in the hand.