Apart from that, even though the great number of demons wouldn’t change at all once the Grade Grande was defeated, it still remained a fact that Grade Grande was an existence unifying them as boss of the domain. Although it simultaneously reigned at the top of the food chain, it apparently likewise instilled such a fear into the other monsters that they weren’t able to move about freely either.
Therefore, if Grade Grande died and thus was missing in the lineup of the monster group, it would become possible for the army to safely crush each and every monster afterwards.