Fire breath. Lowers weapon def. and magic res.
Reduces target's defense.
Guard Off (Off Guard in some translations) is a Blue Magic spell that lowers enemies' Defense. It can be learned from Page 256, Magic Dragon, Shadow, Ziggurat Gigas and Azulmagia. It cost 19 MP to cast. Ushabti, while technically having the attack, can never use it as it cannot have enough MP to use it.
Off-Guard is a Blue Mage spell that can be learned by using a redeemable token awarded by the Wayward Gaheel Ja in Ul'dah after learning 15 Blue Spells. It increases damage dealt to a target by 50%. While it has a recast time of 30 seconds, the timer is reset if the target is defeated before the effect expires.
Expose Weakness is a Blue Magick spell learned from Fire Drakes that reduces a unit's Defense and Magick Resistance. The spell costs 8 MP to cast and can hit a target up to 4 tiles away from the caster.