When the fierce power from the ballistae was added, things became out of control for the enemies.
Every single bolt exploded, and a huge pillar of fire erupted. It wasn't only that, but the shockwave erupting from it was strong enough to push away all the enemies around in a large area, making it impossible for anyone to come near that area for many minutes.
With that support coming out to the stage, things became much easier for Sloth and his handful of selected teams to secure a path for the incoming masters from outside.
That wasn't all! Few of the masters pointed their ballistae toward the incoming army of monsters from afar. The monsters were still a long distance away, separated from them by mountains and hills. But with such fierce explosions, the already established paved routes got blocked by tons of rocks, falling from the mountains and hills around.
