A scarlet crack in the void penetrated the sky, like a wound in the abyss, and endless alien races swarmed out of the crack, like a huge wave sweeping the earth.
The fire of human civilization is swaying in the wind and rain, and may be extinguished at any time. In the darkest moments, one strong person after another stands up and builds high walls with their flesh and blood, barely resisting the tide of aliens.
In the end, humanity won a brief respite and peace.
However, the crack still hangs in the sky, covering the earth like a nightmare, indicating that the shadow of the alien race has never really gone away.
And under this seemingly calm surface, there are undercurrents surging, hiding unfathomable crises, as if ready to tear this fragile peace apart at any time.
Concept: alien invasion, protagonist savior