Seer: The Demon Lord Returns

Ten thousand years later, the Chaos Demon Lord, who had once vanished, returns. But the only person in this world who could stop him is long gone.

The Demon Lord emerges, leaving no survivors. Blood flows like a river.

Under the rule of brute force, must all living beings submit?

Set on another world's continent. Only the characters' backgrounds are changed to fit their original characterization. No breaking up canon couples, and no making characters stupid.