Twenty Kingdoms

Clover: If we assume those people were wiped out by some "enemy," it means those enemies should have survived later in history. Coincidentally enough... 800 years ago, at the end of the Lost 100 Years, was the precise birth of today's "World Government." If the enemy of those eradicated peoples is our World Government.

Clover, Chapter 395

Pappug: Because they have the blood of the Creators in their veins...... Eight hundred years ago, a group of twenty Kings... ...formed a mighty organization known as the World Government.

- Pappug, on the World Nobles. Chapter 497.

The 20 Kingdoms or known as the Ancient Alliance are the 20 kings of their kingdoms combine to become an Ancient Alliance that became the World Government. During the Void Century they fought against the Ancient Kingdom, by 800 A.O.S the Alliances became the World Government. The World Noble are descended from these kings.

First mentioned in chapter 395 by Clover, they were fully explained 102 chapters later by Pappug. Why or how the 20 Kingdoms overthrew the Ancient Kingdom is a mystery.