Artillery
Gives the hero manual control over the Ballista, increases its number of shots per round to two, and increases the ballista's chance for dealing double damage. Also allows the hero to manually control the Arrow Towers during a siege.
Recommended for: Secondary Heroes in the early game for clearing neutral stacks (in big late game battles the Ballista won't last long) and heroes who defends castles, as controlling the arrow towers can be very valuable during castle sieges.