"In Darkness eternal they searched,
For those who had goaded them on,
Until at last they found their prize,
Their god, their betrayer:
The sleeping dragon Dumat. Their taint
Twisted even the false-god, and the whisperer
Awoke at last, in pain and horror, and led
Them to wreak havoc upon all the nations of the world:
The first Blight."
No one knows what it is that drives the darkspawn in their relentless search for the sleeping Old Gods. Perhaps it is instinct, as moths will fly into torch flames. Perhaps there is some remnant of desire for vengeance upon the ones who goaded the magisters to assault heaven. Whatever the reason, when darkspawn find one of these ancient dragons, it is immediately afflicted by the taint. It awakens twisted and corrupted, and leads the darkspawn in a full-scale invasion of the land: a Blight.
Entering the Dead Trenches and seeing the Archdemon: Urthemiel was once the Tevinter god of beauty. In ancient times, he was worshiped by musicians, artists, and poets. The Feast of Urthemiel was the grandest celebration of the year, an event that lasted a full twelve days. Plays and entire symphonies were written in his honor. Now, he is a maddened husk of his former self, filled with nothing but a desire to destroy all life.
After Riordan reveals the truth about the Archdemon: When the first Blight began, many brave men and women threw themselves at Dumat, the first archdemon, trying to strike him down. But no matter the numbers, no matter their strength, he would always return. This was proof, some said, of his divine power.But the Grey Wardens soon learned otherwise. Their tainted blood bound them to the archdemon, and they could hear it, feel it, as it died and was born anew, its spirit drawn to possess the nearest tainted creature. The darkspawn were mindless, soulless, empty shells of flesh that could be bent and remade in the dragon's image. But a man... a man's soul was not so malleable. When a Warden's hand struck a fatal blow against Dumat, the Old God's spirit was drawn not to a darkspawn but to the man who had slain him. In that moment, the souls of both the Warden and the archdemon were utterly destroyed. And the dragon rose no more. The Blight was over.