I once met a darkspawn that was unlike others. He called himself the Architect. He spoke, and was surprisingly intelligent for a Darkspawn. He even made other talking darkspawn.
He didn't control an archdemon, though. That's more than a little horrifying. What he did do was, apparently, try to end the Blights and was instead the reason for lucky Blight number five! Funny how that works out.
I'm sorry, I was reminiscing on happier times (he says, as though Thedas ever has happier times har har). The point is, I wonder if they're connected somehow.