Southern-Central Japan, Many years BCE

If the stories passed down from his parents were any indication, the land between the ocean and the mountains had been home to Kou's people since the beginning of time. Therefore, the strange folk who had arrived on giant boats generations prior and displaced his tribe were an unwelcome blight on what had once been paradise on earth. 

Kou hated those people with all of his being, for they spoke an ugly language, filled entire stretches of land with their so-called rice crops, and routinely cut down trees to house their ever-increasing numbers. 

If nothing was done to stop the invaders soon, Kou's people would be conquered and forced to assimilate like so many before them. And so, one morning, he gladly joined the other young adults of his tribe in praying to their bird god so that they would receive divine favor in future battles. 

Little did they know, an event of similar religious significance was being conducted by their enemies at that very moment. 

******

As the oldest daughter of the village leader, Namu's presence at the religious ceremony was all but required. Wearing a long white robe and a crown of leaves upon her head, she accompanied her mother and father in bowing to a statue of the heavenly dog worshipped by their ancestors in the old country. 

Namu remembered the stories of how her people had been forced to flee by boat to escape a war of such cruelty that the earth itself had shed tears of blood. It had been a stroke of luck that her ancestors found land perfect for farming, though the primitive inhabitants had been less than willing to share their territory. 

Of course, that would no longer be a problem in due time. Many of those same primitives who had resisted occupation in the beginning had eventually surrendered in favor of what was clearly a more prosperous way of life than hunting animals and picking at wild plants. 

Only one stubborn tribe remained in their vicinity, and Namu knew that their defeat would be guaranteed the moment her father marched on them with his much larger army. A faint smile spread across her face in anticipation of the prisoners who would be lined up in the center of the village and forced to perform the filthiest of labor as punishment for their resistance. 

******

The sun continued its steady ascent in the sky as two opposing armies confronted each other at the foot of the mountain which marked the edge of their land. The men of Namu's village readied their iron and bronze weapons, while the members of Kou's tribe brandished their spears in the most menacing way they knew how. 

Unbeknownst to the two sides, a mysterious creature was watching them in amusement from the safety of his mountain refuge. He raised his birdlike head and gave out a taunting shriek, for he knew that one day, the descendants of those foolish mortals would worship him instead.

He would make sure of it.

******

Author Notes:

I've wanted to write something set during the Yayoi period for a while, so I'm glad to have finally gotten it over with. It's not too obvious, but the creature at the end is a future Lord Tengu, which essentially makes this a stealth backstory.

Very little is known about the Yayoi period due to the absence of writing, but the Jōmon and Yayoi people are generally believed to have been two separate groups that merged over the centuries. The origins of the Jōmon are unknown, and they may have come from a multitude of locations across Asia.

The origins of the Yayoi are a little less mysterious, with the most accepted hypothesis being that they were ancient migrants from Korea and/or China. The population of Japan increased significantly as a result of their arrival, due in part to the spread of rice farming. 

I took some artistic liberty with the characters' names, since there is no way of knowing what Japanese sounded like this far back in history.