Lineup changes are very much the norm in black metal; a black metal band that can go ten or more years without any lineup changes is the exception instead of the rule -- and like so many other European black metal outfits, Dark Fortress have had their share of personnel changes since their formation in Germany in 1994.

Dark Fortress experienced some major upheaval and turmoil in 2007, when their original lead singer, Matthias Jell (aka Azathoth), took off after 13 years with the band and was replaced by Morean (founder of the band Noneuclid).

But Dark Fortress bounce back nicely on their first post-Azathoth album, Eidolon.

This 2008 release is a concept album based on the Greek idea of an astral double, which is similar to the German concept of a doppelgänger.

Some concept albums work well as a whole but lose something if you only hear selected or individual songs; however, that isn't a problem at all on Eidolon.

Every song on this 52-minute CD can stand on its own regardless of whether or not one hears the other tracks; that is as true of "The Unflesh," "Catacrusis," and "Cohorror" as it is of "Edge of Night" (which has nothing whatsoever to do with the American film noir/crime thriller-themed daytime soap opera that ran from 1956-1984 -- first on CBS, then on ABC -- although the song's title will bring smiles to the faces of those who are old enough to remember that program).

Brutally heavy yet darkly atmospheric and fairly melodic, Eidolon achieves a stylistic middle ground that fans of more mainstream metal might find to be more accessible than Gorgoroth or Marduk but less accessible than Dimmu Borgir.

Morean sticks to sinister-sounding rasp vocals and never ventures into clean vocals, but he doesn't render the lyrics indecipherable -- and he proves to be a major asset for Dark Fortress throughout the excellent Eidolon.