War machines in Heroes V.

But the enemy hero won't be able to keep attacking endlessly if there are 100 or more imps in the army:D. Also, we can place the gate right next to the enemy archers.

You misunderstood me; here, I meant the gate to the castle and different races. Also, the heroes are already out of mana at the end, the flying units, archers are either dead or out of arrows, and the heroes are just using their regular power attacks (the people will be inspired). And the towers in the castle also shoot endlessly. I don't think many people would want to sit in the castle and watch this pathetic and long spectacle.