This is absolutely incredible. I'm going through Demon's Souls for my first time in an effort to finish it before Bloodborne comes out (I started with Dark Souls 1) and I was listening to Windmills while I found a link to this on Tumblr. You've captured the grim yet peaceful atmosphere perfectly.
Well I didn't ask if there was such character in the Nexus. I just wanted to know if that was the nexus in the backround. I haven't played through DS very much at all actually, so I wouldn't know what the characters are in it.