Okay so I like to think of Thedas as a world that's constantly going through horrible bloody change each cycle. Entropy drives it forward.
Thedas was once whole. The Sun resided in the Earth. Beyond that, nothing. The Balance was pristine.
Then one day some mysterious circumstance shifted the Balance violently and caused both to split. In doing so, the first stirrings of life bled out. The First Children were the Pillars of Earth and Sky. Like the world, both were intrinsically connected. The Pillars of the Sky took the form of primordial dragons, beings of pure thought. Pillars of the Earth were the titans, the land itself.
As the First Children shaped the Earth, many new beings were born out of them. Notably, the spirits and the dwarves, later the elves. Then the elves fought against the Pillars for their very existence, unaware that their presence threatened the balance that many Pillars thought they needed to uphold.
As the Balance continued to tip, the hole in the Earth's 'chest' began to fester. The Void grew in strength and the Blight was born.
Then came Solas, who again tipped the scales to buy more time. The formation of the Veil only served to tip the Balance the other way. It did not stop the Blight from whispering to humans.
