Era beginning/end
Once, long ago, the world of Veridia's primary inhabitants were the mighty dragons. That all changed when the chromatic dragons, under the tyrannical rule of Tiamat sought to destroy the metallic dragons, under the benevolent leadership of Bahamut. The Chromatic War, also known as the Great Dragon War, brought the world to turmoil. Entire cities were destroyed, landscapes transformed forever, countless lives were lost. It was only by banishing the Scaled Tyrant, Tiamat, to the Nine Hells, that the war was won, and a new Era began.
Before the Fantastical Era, mighty dragons roamed the earth. Metallic dragons lived as leaders among the lesser but free humanoid races, while chromatic dragons formed their own dictatorships, enslaving the humanoids. It was common to see even a hundred dragons in such a place. The enslaved people under the rule of the chromatic dragons hated their overlords, but they were helpless on their own, so they sought help from the metallic dragons and their famed armies. The metallic dragons, who never trusted the chromatic dragons for their entire history, pitied the oppressed humanoids, but regardless did nothing, fearing the consequences of an unprovoked incursion. It wasn't until the assassination of a well known silver dragon that set off the events that follow. The metallic dragons blamed this crime on their chromatic brethren, while the chromatic dragons claimed innocence, and fought back against this perceived injustice. It wasn't long before the dragons sent their armies upon each other. The land, sea, and the skies were ravaged by fire, ice, acid, lightning, and toxin as the dragons fought to the death. So great was the conflict, that the gods Bahamut and Tiamat themselves did battle, themselves. It was the first and only occasion the divines intervened in a mortal conflict since the first days of the world. In the end, the humanoids claimed victory over the chromatic dragons by banishing the Scaled Tyrant, Tiamat, damning her for eternity in Avernus. Bahamut, gravely wounded by his counterpart, was forced to return to his home on the upper planes. Countless dragons were slain, and far more humanoid lives were lost, but that was only the beginning. The humanoids realized the power they had within them. With far fewer dragons in the world, they realized they could take charge of their own destiny. The newly liberated slaves of the chromatic dragons took revenge against their masters, and sought out and destroyed the chromatic dragons who remained. The armies of the metallic dragons also realized that they did not have to obey their masters, and they turned on the metallic dragons, slaying many of their kind, and forging their own independence. The aftermath of this slaughter can be seen to this day, in a vast graveyard of dragon carcasses, high up in the mountains of what is now Titan's Rest. For years since, dragons remained in solitude, knowing their era of history has ended. Centuries passed, and a dragon sighting is such a rare occurance, it is often seen as nothing more than a legend or a madman's ramblings. Though the people have forgotten, the dragons haven't. Chromatic and metallic dragons hate each other to this day, often fighting to the death if they encounter each other in the world. But most of all, they have not forgotten the betrayal of the humanoid races either, and, though many metallic dragons still enjoy the company of humanoids, they know better than to trust them.