This is a tale from a distant past.
The nations of the Western Continent were once threatened by the demonic tribes who dwelled across the Mediterranean, in the Dark Continent to the south.

But in the face of this dire crisis, humanity, after a grueling and deadly struggle, managed to repel the demon invaders.
And after more than a decade of war, they finally brought the demonic forces to ruin.

Centuries passed, and the memories of the war against the demons began to fade—until one year...

A calamity brought by Chaos struck the Dark Continent, which had since come under the rule of the Allied Nations.
Chaos—a grotesque anomaly that parasitizes humans and animals alike.

The calamity spread from the southern Dark Continent to the Middle East, then to the East, and eventually reached the Western nations as well.

This creeping disaster—the Crawling Chaos—ultimately destroyed an entire kingdom. Only the princess managed to escape the fallen castle.

But even she found herself being pursued by the forces of Chaos.

Just as all hope seemed lost—

Riding the wind, a black-haired girl appeared and declared her name.

“I am Satsuki! A hero reincarnated from another world!”