It is said the world is divided into five eras: The Green Era, the White Era, the Red Era, the Blue Era, and Yellow Era, each lasting a thousand years.
The Green Era was simple: It was age of primitives and animalistic behavior, where there was no to little civilization.
The White Era was the beginning of Civilization. There was relative peace and vast advancement, but there was still war.
The White Era ended and the Red Era began with the rise of the First United World Empire, whose name has been lost to time (Legend says that it's Barbaria, land of Barbarians). It attempted to unite the world under a single flag, but failed as rebels and coalitions forced the empire to collapse. Unfortunately, the coalition was unable to decide the division of the First United World Empire, and so they waged war to attempt to get a better deal, or even to form their own United World Empire. This was the beginning of a thousand years of consistent war and no development (and even regression)
This era finally came to a climatic end with the rise of the Second United World Empire (Helskeck) and it's destruction. The united coalition convened in it's capital to discuss the future of the world, where they signed the Blue Treaty, officially ending the Red Era and beginning the Blue Era. The Blue Era said that the World was to be divided into 5 spheres of influence: Malpen, the Great Continent; Kols, the Southern Continent; Ident, the Western Continent; the Pulmars, the Central Sea Islands; and the Gulmars, the Far Eastern Islands. The treaty said that Nations could wage war within these sphere of influence but not outside (or, more specifically, couldn't expand outside). The Blue Treaty would be followed for a thousand years, with empires constantly uniting the sphere of influence before falling apart do to inside sources.
Sadly, the Blue Era could not last forever, for a new empire from Malpen attacked Kols and took large sections of it, declaring itself the Third United World Empire. This was the end of the Blue Era and the beginning of the Yellow Era, the current era. War is much more common in this era, but not as much so as the Red Era. United World Empires are constantly rising and falling, but we have only 50 years left of this Era. We can only imagine what will come in what some prophets have already started to call the Grey Era.
So far there has been 6 United World Empires in the Yellow Era:
The Maplen, whose Empire collapsed after its invasion of Kols.
The Gulmars, invaders from the Far Eastern Islands. Gulmar was one of the longest lasting, lasting 200 years before finally being repelled from the continent of Malpen.
Rundel, another empire from the continent of Malpen, immediately successors of the Gulmars by conquering them, they were also one of the shortest lived empires, dying in about 10 years.
Jaris, an empire arising from the continent of Ident and successfully united Ident and the Pulmars, but lost in their invasion of the continent of Malpen. They coasted for another 50 years, before grand revolution saw the fall of Jaris.
The Pulmars, successors to the fall of Jaris. They started off as a confederation before they set off towards Kols and Ident. They became the largest empire since the First United World Empire, but their fall was one of the harshest.
The current nation that takes the title of United World Empire is Sharodel - The eighth and so far best attempt to unite the world under a single flag, a nation from the western most part of the continent of Kols. They broke free during the fall of the Pulmars, quickly uniting the region of the Pulmars with a decade. They're currently on the march to unite Ident.
According to prophets, they say that the end of the Yellow Era will come with either the definitive defeat or victory of Sharodel at the islands of the Gulmars, with the Grey Era being a thousand years of United World, or a thousand years of peace among the continents.