I think the rather ugly split with ICS Vortex and Mustis is part of what halted their momentum. "In Sorte Diaboli" was still a popular album after all (it went to no. 1 in Norway). Another reason for this is probably the fact that they aren't nearly as prolific anymore. 8 years between "Abrahadabra" and "Eonian" and 5 years since the latter... quite long stretches of time there. They also don't tour as frequently anymore.

Also, you can feel the loss of ICS Vortex and Mustis on these last two albums. "Abrahadabra" is disjointed and "Eonian" is just kinda boring imo. I know they weren't always part of the band (and my favorite Dimmu album - "Enthrone Darkness Triumphant" - has neither of them) but they eventually became a core part of their sound. I'd argue the addition of ICS Vortex in particular helped get them where they are. The clean vocals in "Progenies of the Great Apocalypse" certainly drew me in and made me a fan. I remember thinking "he sounds like Marco from Nightwish!", lol.

Yeah. I had a quick read after this post. Vortex is on record saying that Mustis had a massive input into the creative process, and it seems his absence has had a negative impact on the more recent records the band has put out. You may well be right about Vortex too. You can't be the only person attracted by Vortex's vocals, and if Mustis did a lot of the work creatively, regardless of him being properly credited or not, that's a massive hole to fill. Dimmu decided to be smart about it and not replace them at all.

ICS Vortex definitely has his fans, for sure. I met a few guys who were into mostly popular and accessible metal, and was surprised that they knew Arcturus, and the reason was that they loved ICS Vortex with Dimmu Borgir and they just kind of kept digging into all the projects he was involved with.

He's a great musician, and his vocal style really stands out in a positive way with Dimmu, even if he didn't sing often or on every song. His contributions always stood out to me. Like, I'm not a fan of Death Cult Armageddon, but his lines on Progrenies of the Great Apocalypse are awesome, and I remember it making a good impression on 17 years old me.

I love many tracks on Enthrone Darkness Triumphant and think it's one of their best efforts, but Spiritual Black Dimensions is where they really peaked, for me. It strikes this interesting production quality of being a bit muddy, but also elegant. It's a thick atmosphere, if you will. They became overly polished from Puritanical onward and lost some of that balance for me. As Dimmu was one of my "gateway" black metal bands, I would call myself a fan but I'm not blind to the fact that a lot of their post Spiritual Black Dimensions output can be quite generic.

As for Vortex, I would definitely argue that his presence in the band helped gain them quite a bit of notoriety, particular on "Progenies of the Great Apocalypse." That was the release I recall as being one of, if not their biggest "breakout" moment(s) and I would argue a large reason for that is that epic bit at the bridge where Vortex really shines. It's such a massive juxtaposition of cinematic quality clean vocals set against a metal background and while its certainly not something Dimmu innovated, it worked perfectly and was captivating enough to really get people's attention. I could be over-estimating how big the song really was since I was around 13 at the time and really only had my circle of friends as a barometer, but that's my recollection anyway.

I'll fully admit that I checked out both Borknagar and Arcturus because of ICS Vortex's time in those bands. Still love "The Archaic Course" and "Sideshow Symphonies" quite a bit. The dude's got a powerful voice. Dimmu Borgir's popularity definitely helped lift those bands up too (and that's a good thing - Arcturus and Borknagar are great, with or without ICS Vortex).

Arcturian is one of the albums of Arcturus I listen to the most, and Vortex really shines as a lead vocalist on it.