A simple passing by the side of the fort turned into a struggling journey through fire and bombardment. By the time the flame dispersed, the orcs at the front finally passed through the backline of the fortress. However, the caltrop's effect was still there, hence most of their front troops still couldn't summon their mounts.
Even though the caltrops broke after getting trampled three times, the ones affected were the ones at the front. Even if the back army could still move normally and use their mounts, they couldn't charge ahead. They had to adjust to the speed of the front army. Otherwise, they would crash into the front army and cause chaos like the first time they were hit by the caltrops on the field. Thus, the overall speed of the army slowed down as if the entire army was under the effect of the caltrops.
