Arrow Storm is a Finesse-based ability where the character shoots multiple arrows into the air, having them rain down on enemies. The ability also increases the size of the quiver.
There are three levels of this ability, though one more level is available via ability bonuses. Level 1 unlocks the Arrow Storm move. Levels 2 and 3 increase its damage by 20% and 40%, respectively; the bonus fourth level increases Arrow Storm's damage by 60%. Unlocking this ability increases the size of your quiver by one.