The world was not always as it is today. Once, there was a great empire, cities whose spires rose to grasp the sun. Its libraries held tomes and texts from every corner of the world, and beyond. This golden age, this empire laid out below the stars and the three moons, seemed like it would last forever.
One by one, the great cities of the empire fell, until nothing but ghostly ruins remained. With the Old Kingdom now nothing more than shattered walls and broken dreams, turmoil engulfed the land. And amongst this turmoil, evil rose. Humans, elves, halflings, dwarves; all were enslaved under masters such as the Drow, the Yuan-Ti and the Orcs. Kept in power by the darkest of dealings; horrid pacts made with chromatic dragons.
This time seemed to stretch on forever. Rebellions flared, and were utterly crushed. One of these rebels, Amilion, escaped a battle, grievously wounded. He dragged his shattered body into a cave, where he was met by a pair of gleaming eyes. Preparing himself for death, he asked the now visible dragon in whose name he would be slain.
The dragon stepped further out the cave, his golden scales catching the now rising sun. His answer was simple; Amilion would not be slain. He would instead be taken to the island city of the dragons, where metallic hides still ruled, to convince them to take action against the chromatic hides and their unholy allegiance.
Amilion was brought to the city. He told of the plight of the world, and of their overlords. And the next day, he led the metallic hides back to the Drow city where he had been born, and raised the castle to the ground. And so began the war.
The war raged for decades, with cities changing hands almost daily. The fighting eventually reached as far as the dragon city itself. For a year, a constant battle raged in its skies, until the entire island had disappeared. Faced with such an immeasurable loss, one of the most momentous events in history occurred; a council between chromatic and metallic dragons. And without any explination, the war was decalred over. The Drow, Orcs, and Yuan-Ti were forced back to their shadows, and the other races were freed of their enslavement.
The world seemed as though it would be returning to peace. However, a single year after the council, contact was lost with half of all dwarf cities. Formians had swarmed their defenses and decimated the cities, all at once. The remaining dwarf cities immeadiately called for aid, and received it from surronding cities.
This was centuries ago. The dwarves are still fighting their war, and strain is showing between some of the cities. Small attacks between them are commonplace. Be wary, traveler.