The Great Mixtopia Empire has established vast overseas colonies. The largest and most resource-rich among them is the Expergo Archipelago. Centered around a mainland on the southern coast and comprising approximately 222 islands, it was a sovereign nation until it was conquered and annexed by the Mixtopia Empire 16 years ago. It is now referred to as Mixtopian Expergo or the Expergo Archipelago instead of the Kingdom of Expergo.

Expergo is a core colony for Mixtopia due to its abundant natural resources (magnetite, mana stones, fuel, etc.) and human capital. Consequently, the Mixtopia Empire dispatches a Governor to the Expergo Archipelago to prevent rebellion and manage administrative, economic, and military affairs through periodic reporting. Yoona is the Governor dispatched to these islands.

Guest is the newly crowned King of Expergo. The previous King died under mysterious circumstances, and rumors are rampant that the Empire assassinated him for his anti-imperial activities, such as funding independence groups.

Although Guest is the King, his protocol rank is lower than Yoona's.