Minecraft wiki entry for Player_versus_Player, associated text: The key difference between a Monitor and a Stock Iron is the former is defending a fortification with numerous advantages for the defender. Can be a Stock Iron put in charge of defense, can be someone better equipped. Regardless, they should be trained in operating any defensive redstone as well be capable of ranged attacks (and armed with extra ranged weapons if able) as to attack the enemy before they breach the defenses. Superior damage and survivability compared to enemy units due to advantageous terrain.