100-Year War

Also known as the Great Calamity, the war that set in motion the change the world needed to regulate the mysterious powers of magicks, discovered in uncovered writings of the past. Increasingly stronger ways to conjure and manipulate the art of magicks gradually created tension between the ever-growing tribes and factions of the world eventually bursting in a world-wide conflict. And the catalyst of this was the emergence of a large terrifying hole in the fabric of reality above the White Mountains in Eastern Kingdoms, pouring through countless of creatures in a frenzy.

Instigation

Several years before the start of the war, a think-tank of several powerful sorcerers was formed in order explore the theory that there could be a new plane of existence, perhaps one parallel to theirs. Manipulated by Weylin Miriel, the sorcerers had begun experimenting until they ripped open a hole to a reality filled with demonic and fiendish creatures.

Aftermath

The war was concluded closing the portal by combined effort of various allies spread across the world. The closure would begin the formation of political worldpowers that promised to offer safety to the people and with it kickstart the industrial revolution.

In addition, the victory solidified alliances across seas which agreed to trading between them - the currency to make this possible, and still in use today, was then agreed upon to be used by all nations of the world (copper, silver and gold are the common trading coins).