“Ooh, I heard everything! Who would have known that star was so important? I've got to inform Smithy.”
An Aero is an arrow-like enemy that was fired by Bowyer during his siege of Rose Town in Super Mario RPG: Legend of the Seven Stars. These arrows are laced with a special potion, allowing them to cause paralysis when they hit their target. As such, Bowyer fires arrows into Rose Town, paralyzing its inhabitants. However, Bowyer has terrible accuracy, resulting in almost all Aeroes landing harmlessly on the ground in both Rose Town and the Forest Maze where Bowyer is stationed.
When Mario is hit by one of these arrows, he will not be permanently paralyzed; rather, he is briefly knocked unconscious. Although Mario takes no damage, being hit by an Aero can be dangerous. While in the Forest Maze, if Mario is stunned, he will be unable to run away from attacking monsters. However, since these Aeroes attacks are random, Mario will most likely never be hit even once.
Shortly after Mario and Mallow discover and hide from Bowyer after stumbling upon him deep within the Forest Maze, they can only watch as Bowyer and his many Aeroes laugh about the helpless citizens of Rose Town. Before they can react, a single Aero is revealed to have found the green Star Piece somewhere in the forest, which he in turn presents to Bowyer.
During Mario's confrontation with Bowyer, Aeroes are used by Bowyer as a standard physical attack and as a Sleep inducing special attack. Additionally, Aeroes are used to lock controller buttons, preventing Mario's party from using certain commands. Eventually, Mario and company defeat the maniacal Bowyer and his Aero minions.
Only one Aero survived this battle; he did so by hiding behind a tree stump during the fight. After eavesdropping on Mario and the gang, this lone Aero rushes to the Factory to inform his boss Smithy about the importance of the Star Pieces.
Aeroes later appear in the Factory. Like in Rose Town and the Forest Maze, Aeroes briefly knock Mario out, allowing enemies to attack the unconscious plumber. Unfortunately, these Aeroes are more accurate than the previous ones, meaning Mario will often be hit and paralyzed. The source of these arrows is unknown, but they are probably fired by an off-screen Machine Made Bowyer. Like the original, these mass-produced versions of Bowyer also use Aeroes in battle.
During the final fight against Smithy, an Aero is one of the minions that warns Smithy against smashing the floor of the platform, which ultimately breaks. This may have been the same one that witnessed Bowyer's defeat.