In Xenoblade Chronicles, Air Slash is one of Shulk's physical arts. It can inflict Break to an enemy and if it is performed on the side of said enemy, it can inflict Slow, which reduce the enemy's movement and attack speed by 50%.
If the art inflicts its Slow debuff, volatile aggro is generated and 20% is added to the Party Gauge. A level 50 Shulk would generate 640 volatile aggro.
The intermediate books are only found in shops for 7200 G
Air Slash appears as one of Nia's physical Driver arts when having the Knives equipped. Air Slash is now a multi hitting attack that can inflict break with its last hit and damage dealt will increase by a certain amount if used while at 90% of your life or above.
The move can be customized in Super Smash Bros. for Nintendo 3DS/Wii U. Those are the available Customization.
Advancing Air Slash: On the upswing, Shulk goes up at a slight angle. The second swing brings him lower but sends him forward. The swings have less delay and the second slash has a bit more knockback
Mighty Air Slash: The length of the attack becomes the size of the Monado itself but it delivers more damage and knockback as a result. Knockback is now more vertical but it is harder to connect bot swings.