The Ram is used to aid your troops in battle by tearing down your enemies' walls. One fact that should be noted is that its attack is separated from your main troop's attack. The Ram will attack the enemy Wall before the battle even starts. Once the Rams have brought the Wall to a crippled state, your main army will commence their attack. Keep in mind that although more Rams will cause the Wall to fall faster, more of the population could be used for other supportive units.