Internal Erosion

About 150 years ago, the Earth, the home planet of mankind, became uninhabitable due to a mysterious super disaster (perhaps environmental collapse, runaway nanotechnology, or unexplained cosmic phenomena), and civilization was almost destroyed. The survivors embarked on a desperate interstellar escape on a limited number of hastily built Ark ships. The next few decades were civilization's darkest hours. The Ark fleet drifts among the stars, resources are depleted, social structures collapse, and conflicts for survival continue. This period of history is the common psychological trauma of all surviving human groups, known as "traumatic memory", and has profoundly affected the values ​​​​of the new civilization - survival, order, and cooperation are regarded as the highest norms. The largest Ark fleets met in several adjacent habitable systems. After experiencing initial suspicion and friction, they realized that division meant destruction. As a result, a republic composed of planets and space stations after hundreds of years of arduous terraforming and ecological cycle construction by humans - the "Pan-Human Star Community" came into being. This is not a loose federation, but a centralized government with strong pragmatism and social Darwinism. Power is highly concentrated in the fleet and the central government to ensure the survival and expansion of civilization. External invasion, internal contradictions, the curtain on the survival of civilization has opened. "History, with its unfinished judgment, turns to another possibility."