See way back in the day, the magisters of this one empire decided it would be a brilliant idea to go to the golden, holy 'no humans allowed here, gods only' city.
The city turned black, and they became corrupted. They corrupted the old gods in the process, and thus came the Darkspawn. Really...darkspawn are terrible. If they don't eat you, they turn you into a breeding pit if you're unlucky enough to be a woman.
Then when an old god wakes up corrupted, they start invading and blighting the land. So I was part of this order that fought them.