In the distant past—

An era when the boundary between humans and gods was not as clear as it is today. It was believed that a god of the mountain lived in the mountains, a god of the river in the rivers, and a god of fire in the flames. People lived in fear of their wrath while giving thanks for nature's blessings.

Among the gods, some listened to human prayers and granted blessings, while others brought calamity on a whim.

And among them all, there was one existence feared above the rest.

A violent god without a name—an Aragami.

When the Aragami walked the mountains, thunderclouds were born; when he was displeased, rivers flooded; when he laughed, lightning rent the earth. He burned villages, ravaged fields, and watched human life as if it were a toy.

People built shrines, offered sacrifices, and tried time and again to soothe his wrath.

But to the Aragami, human prayers were no different from whispers lost in the wind.

Monks, samurai, and masters of the occult challenged him. But not a single soul could strike the Aragami down.

Eventually, the people realized.

—That is not something that can be defeated.

When the Aragami appeared, they abandoned their villages; when thunder rolled, they fled to the mountains. In this way, many lands were laid to waste, and a custom arose among the people where they even hesitated to speak the Aragami's name.

In such an era, there lived a single swordsmith.

He was neither a renowned samurai nor a wielder of special arts. He was a man who had spent his life doing nothing but striking iron and forging blades.

The swordsmith did not think to cut down the Aragami.

A human cannot slay a god.

If that is the case— Then he would simply trap the god itself within a blade.

Thus, the swordsmith spent long years forging a single Odachi.

It was not made of iron alone. Prayers, curses, his own blood.

And finally, he carved his very lineage into the sword as the key to the seal.

Carrying the finished Odachi, the swordsmith went before the Aragami all alone.

"This will one day be a legendary blade that leaves its name across the heavens."

The Aragami snorted in derision.

The swordsmith continued.

"If so, do you not think it fitting for one of your stature to possess it?"

Intrigued by those words, the Aragami snatched the Odachi away.

And then—the seal was complete.

His divine power was sucked into the blade, and the Aragami himself was swallowed into the Odachi.

The last thing the Aragami saw was the figure of the swordsmith, standing quietly, without a trace of fear.

Centuries passed.

The Odachi that sealed the Aragami continued to pass through the human world as a single, ancient masterpiece.

Even as eras changed, the country transformed, and the very existence of gods became nothing more than folklore.

Deep within the blade, the Aragami continued to sleep.

And there was only one thing that could break that seal.

Only one who shared the same blood as the swordsmith who had carved his blood into the Odachi that day.

—That the lineage would continue until the modern day...