The demons fortified and are ready as the human army starts pushing forwards the demons use there main infantry first and knights and archers mages are as a last resort to defend the kingdom.
The demon army of 300k Vs 600k human soldiers the humans are bad at magic so the demons have advantages in destructive magic they fight back with force on the first day the human army loses 150k to demons losing 30k the casualties are high but the demons still are at danger it's 270k Vs 450k.