There were several reasons why monsters were constantly attacking Japan, but there was one more that had yet to be explained.
What was it? To put it bluntly, population control.
Monsters needed to eat, too. While some could farm fields and such if ordered to do so, very few demonkin actually knew anything about agriculture, fishing, or livestock—or anything involving food production, in fact. More importantly, demonkin weren’t the patient, hardworking type. They hated slow, tedious tasks.
As such, they enslaved the populations of the lands they conquered and forced them to work in the primary industries.
But no matter how much land and how many resources they might have, neither were infinite.
On top of that, smaller monsters acted a lot like wild animals. They could reproduce at an alarming rate.
They were also omnivores that would pick at the crops humans grew—or worse, pick at the humans themselves.
Technically, small monsters served as food for the medium and large ones, so in that sense, they did contribute to the food chain. But to the demonkin—who had human preferences due to their humanlike intelligence—they were nothing more than dumb pets, constantly hungry but of little combat value.
The same went for the medium and large monsters. They also had to eat, and the bigger they were, the more they consumed.
They might have been a force to be reckoned with, but it was tough to maintain a menagerie of large monsters when each one required dozens of tons of food each day.
As such, the demonkin picked the weakest and most inefficient monsters, who consumed too much for what little value they offered, and sent them into battle.
If they drowned on the way over, so be it. But if they managed to swim across the sea and reach Japan, the National Defense Forces would be forced to respond and burn through supplies. And if the monsters managed to take out a few soldiers, then all the better.
Of course, the monsters didn’t know any of this. They just swam as hard as they could. And if there was an enemy waiting for them when they landed, they also fought as hard as they could.
Since the ones that made landfall were eliminated, there were never any survivors left to pass on what they learned. The demonkin didn’t expect them to return, either, so their behavior and tactics never changed.
The monsters always came on land the same way, fought the same way, and died the same way.
That was their fate.
…Until one day, when a newly born demonkin voiced a simple question about the monster hordes preparing to cross the sea.
“Why do they all swim alone? Isn’t that why so many drown? Wouldn’t it make more sense for the big ones to swim slowly, while the medium and small ones ride on their backs or get towed along to save their strength?”
It wasn’t an order, but the suggestion had come from a higher-ranking demonkin. And more importantly, something in the monsters’ instincts clicked. They understood that this plan would help them stay alive and carry out their mission more effectively.
The monsters may not have had intelligence, but deep down, something inside them was screaming, I don’t want to die for nothing. I want to fight like I was ordered to.
From that point on, tank-style transportation tactics—previously a tactic only used by the extra-large monsters—began to spread among the large class as well.
They were like migratory birds flying in formation to manipulate air currents and reduce fatigue.
And what was the result when the invading monsters adopted this simple yet devastatingly effective new mode of travel?
The answer would be revealed just a few days later—when Japan’s Second Division, holding the defensive line across the sea, found out the hard way.