Explosive Arrows

Hero archers who have attained a sufficient level of power may learn how to fletch highly deadly explosive arrows. The art of fletching such projectiles is particularly intricate and time-consuming; it also tends to incur great exhaustion. Because of this fatigue, Archers may find it difficult to fletch many explosive projectiles in quick succession.

hero archers and fusiliers can learn this skill at sub-lvl 250. there's currently no help file for Explosive Stones but they work the same as the arrows except in slings instead of bows.