Lurgy

Lurgy is one of 's ether s in Xenoblade Chronicles. It involves him spewing poison in a cone, applying a highly damaging debuff to all enemies in front.

Overview
If Lurgy is allowed to run for its duration, it deals 6.00x worth of damage for only 0.40x worth of aggro (without upgrades), which is very good indeed. The fact that it also affects multiple enemies makes the total damage even higher. Combined, Lurgy is an excellent art to start battles with, and there is little reason to not simply use it when it becomes available.