Meeeeeeeepppp

I spy a cutie

Basically the beasts attack a city on the other side of the archway (as per its name, Gate), they get wiped out, Japan marches through with tanks and APCs to set up a recon force, they fight dragons, villages and convoys get burnt by dragons, and the medieval royal court wants the war to continue

Imagine (roughly) a modern military force from Japan first being attacked by fantasy creatures and beasts coming through a giant archway only for the fantasy beasts to get wiped out and Japan matching through to the other side. I won't spoil much but the whole effort is to end the war for both sides