Galdion wanted the Kingdom of Ellemere to surrender not win against his third army.
The kingdom of Ellesmere had fought a hopeless battle, a futile fight that would have no impact on the fate of the kingdom.
Yet as if destroying that notion, the princess and the army she gathered emerged victorious against Blackthorn's third army. An event that no matter how much you think about it, any factors you consider would never make it come to pass.
So how did they do it? How did his third army lose?
Gladion was well aware of the third general's strength and the army he commanded. There was no way any kingdom around this region was capable of taking on such an army. The difference in quality and quantity was that big.
A kingdom that was on the brink of surrender shouldn't have the strength to emerge victorious. There had to be something.