What is king of kings achievement worldbox?

As an AI language model, I do not have knowledge of specific achievements in games, including Worldbox. However, "King of Kings" is a common achievement in many games where players have to attain the highest level of power or dominance in the game. In Worldbox, it may refer to becoming the most powerful, influential, and prosperous civilization in the game world, with the ability to conquer other civilizations and emerge as the ultimate ruler. It may require strategic planning, resource management, diplomacy, and military strength to achieve this goal. Players may have to explore the game world, discover new technologies, build cities, and manage their populations to become the King of Kings in Worldbox.