Ash Age Era

AD 4200. It has been two thousand years since humans left the earth. During the long interstellar expansion, human civilization grew in all directions like a giant tree, eventually splitting into several interstellar political systems that were completely different from each other. They have a common origin, but they have long forgotten that they were branches of the same tree. Today, an unprecedented disaster is spreading inward from the edge of the Milky Way - an anomaly called the "ash tide" is devouring one galaxy after another. All matter touched by it will lose its basic physical properties and turn into nothingness. No one knows where the ash tide comes from. But along its path, all civilizations face the same choice: unite, or perish. However, instead of facing the abyss, what humans are better at is killing each other on the edge of destruction.