The war in the empire was fierce. The Duke Wallenstein faction plus Marquis Baldwin fiercely fought the Duke Manstein faction. Due to their numerical superiority, Marquis Baldwin and Duke Wallenstein had the upper hand. His troops repelled Duke Manstein's army and inflicted heavy losses on their side.
After all, apart from getting help from the Moskov empire, their side also got help from the other. The aid was enough to fund most troops, even to make contracts with mercenaries.
Meanwhile, the troops from Duke Manstein and Marquis Welden's side were massively demoralized. Apart from starvation, they are also affected by the disease. The disease they suffer from food that is not proper or dirty water is a possibility.