8 Possibilities That Could Happen If Eren Yaeger Successfully Destroys the World, Paradis Island Becomes the Only Civilization?

Without external threats, internal conflicts within Paradis Island may arise. Differences in ideology, power, and control over the remnants of outside world technology could create internal conflicts that divide the Paradis society.

Children and future generations born on Paradis Island will grow up in a world haunted by memories of the atrocities of the Rumbling. The collective trauma from Eren's actions could create a society filled with fear, guilt, and perhaps a desire to atone for their ancestors' sins.

Rumbling, involving thousands of Colossal Titans walking across the land, will cause severe environmental damage. In addition to destroying civilization, the global ecosystem will be disrupted, leading to long-term environmental disasters that could also affect life on Paradis Island.  

With the outside world in ruins, Eren (or his successor) may have absolute control over all Titan powers. This could make them the absolute rulers of Paradis Island, or conversely, Titans could become a new threat if not properly controlled.

After the global destruction, there is a possibility for the inhabitants of Paradis Island to rebuild civilization with new values. Without the influence of the now-destroyed outside world, they may create a completely different society, both in social, economic, and political structures.

With the entire world destroyed, the history of civilization that existed before the Rumbling will be lost. Future generations may never know what happened before Eren destroyed the world, creating a completely new historical narrative based on what the new rulers desire.

Although the world is destroyed, there may be remnants of humanity that survived the Rumbling who then rise against Paradis Island. This resistance could develop into a new threat to the survival of Paradis, initiating a new cycle of conflict and war.

With the entire world destroyed, Paradis Island will become the only place inhabited by humans. This could lead to total isolation, where the next generation will never know of the existence of the outside world that once was.