Armory shield upgrades affect the pierce armor of all human soldiers, heroes, and ships: those trained at the Academy, Barracks, Military Barracks, Counter Barracks, Longhouse, Dock, Migdol, Fortress, or Hill Fort. They do not affect myth units or siege weapons. Pierce armor protects a unit against pierce attacks, which are generally ranged attacks such as arrows. The armor percentage is the amount by which the attack is reduced.