Which makes the Blight a tool, not a force of nature
Nuclear fusion is a force of nature that's used as tool. Fire is used as a tool. The Old Gods manipulate the Blight, but it may well be a force of nature, not unlike power from the Fade.
Favorite minor character. I hope that guy is doing ok. I let him live. I liked the epilogue said he was helping travelers. i'm sure he was entertaingly wacky about it. DLC WITH THAT GUY!
My issue with "the song" is that so many things are described as having a song. The Fade sings, uncorrupted Lyrium sings, corrupted Lyrium sings, blighted creatures hear a song even without an Archdemon raging(The Calling). I feel like something is just calling to people/things that are tuned either naturally/unnaturally to some sort of frequency. I don't think it's an Old God...if it's something, it's something much older. Something that exists in reality and out of it, because Justice talks about hearing it in The Fade.
He was like the Cole of darkspawn. Poor guy, my Surana had a no mercy policy with darkspawn because of the risks.
As Cole says, they all sing, but never the same song. The Calling from the Blight is coming from the Old Gods, we know that much. That's why the darkspawn seek them out, and the Grey Wardens hear them too when their corruption is bad enough or a Blight is on. Remember when the Warden dreams of the Archdemon? Of course, there's that one story about that Warden-Commander who delayed going on his Calling and believed he was communicating with some ancient elven princess...hm.
He does mention them, when you say "should I ride in on a white steed?" There's also an astrarium that links the halla and griffons, even though Colonel hates to be reminded of it. 
Oooo.... This is intriguing... 