Since the fourth prince had already sealed his fate, there was no way out for the second prince.
After these words from him, the fourth prince's men didn't hesitate to throw everything that they had at the second prince.
The weapons that they used also changed.
These were weapons that had a magical fluctuation coming from them, so they were like the shields that the fourth prince's men used. These weapons being thrown were all magic items.
With the power of these magic items, they crushed through the shields of the second prince's men and destroyed their formation. Once the shields were crushed, they had no way of defending themselves and many of them fell under these weapons.
When it was all over, there was only the second prince and a few of his most trusted men who were left.