Ducitora

Ducitora, popularly known among the Five Kingdoms as the Iron Empire, is a massive Kingdom across the Ocean from the continent where the Five Kingdoms are located. It was ruled by Empress Azura for over a thousand years until her death in Book 3, Chapter 16. She oversaw the transformation and technological advancement of the realm.

Due to it's technological edge over the Five Kingdoms, it also has a superior military. The military edge possessed by the Iron Empire allowed them to threaten the very existence of the Five Kingdoms before the events of Book 1.

Trivia:

 * While the Five Kingdoms seem to resemble Medieval Europe, Ducitora, particularly Marossi, the capital city, seems to resemble typical advanced Western City.
 * T he map of the Five Kingdoms resembles a map of Western Europe while the map of Ducitora resembles North America, specifically Canada and the United States.
 * Ducitora's status as an Empire (compared with Stormholt, Bellmere, Abanthus, Fydoria and Ebrimel which are "Kingdoms") and its massive size suggest it might have been divided into several smaller kingdoms in the past.