Fall of Avtek
As the dust finally cleared and the ash settled, what was left of Vaasa would make any man wretch. Decaying and devastated bodies, blood soaked earth, and twisted smiles were strewn about when those who remained could see. From Telos City to Palischuk, buildings were ravaged, and those unfortunate enough to survive the massacre were taken as slaves, forced to build a new, grander city. This army that conquered was lead by an ambitious, vile being named Avtek. He was by all means far beyond that of a human, and rumors say that he was part demon-kind. Those who stood before him fell like a baby lamb before a starved giant. His army, which was amassed so quickly, seemed to have appeared out of thin air. No one knew anything about him, yet rumors spread throughout the veins of the world like wildfire. But the bottom line was, he could not be stopped.
This was twenty-seven years ago. His dark city was erected, shelter for all dark and damned creatures, his motives all unknown except for one: The bloodshed and conquering of everything between him and the Sea of Fallen Stars. He had conquered many towns and cities alike, those few who rebel against him forming a rebellion called Shadow’s Dawn, an ironic name meaning the dispelling of the night and rising of the sun.
However, this is spoken wearily of, for where this adventure takes place is far, far to the West, beginning in a port called Waterdeep…... and put in the description of your campaign.
After that, take a look at your wiki. There is some more helpful info there.