Swansong? Dude, Dimmu Borgir is alive and well and they haven't released an album that made me feel the band was dead to me
They've come a long way since "For all tid", which may not have the same effect on a new listener, but was one of the standout albums in the genre when it came out. I know some people feel they gone too far with the symphonic stuff, but I love the progress they've made. My personal favourite of theirs is "Puritanical Euphoric Misanthropia". Others will disagree and say "Spiritual Black Dimensions", but "Puritanical Euphoric Misanthropia" is their masterpiece imo. I don't think they'll ever top that one, but they've continued to release great albums imo.
I think there's a new album coming in 2016 and I'm looking forward to it.