Vehemency
In case you are going to give this a go for the first time, I suggest you to turn down the volume a bit. This album is mixed in a way that won't exactly embrace your eardrums, to put it this way. This is indeed not a "delicate sweet" nor an audiophile recording, actually this isn't far from noise when it comes to the production.
But what is hidden beneath the wall of noise is utter beauty. Sielun Kadotuksen Sinfonia (Symphony of Soul Perdition) is, in fact, a very melodic black metal release. While being very fierce and probably the coldest black metal album you can find out there, it still has very melancholic and melodic touch everywhere. It is possible due to the use of synths (you heard right) and also distinct lead guitar melodies in the right channel. Drums are programmed, but I can tell you that they shouldn't bother you: they are mixed quite down, except the toms that are relatively high and used in majestic transitions. Thus the programmed drums are just a unique feature of this album, without them it certainly wouldn't be the same music.
Majestic is indeed a good word to describe Sielun Kadotuksen Sinfonia. Lyrically the album is very passionate and clearly very personal to its maker. Lines like "The blood will not drain from my wounds as my heart is being raped over and over again" are sung in a way that almost freeze the listener (that is if you can understand Finnish, the line above is just a translation). The overall theme of Sielun Kadotuksen Sinfonia revolves around an esoteric concept of Satan and is thus a real jewel for those who are interested in in-depth occult lyrics. In fact, the lyrics of "Asura" are provided by Johannes Nefastos, probably the most known author of occult Satanism in Finland.
Now that it's been five years since its release, I can still honestly say that Sielun Kadotuksen Sinfonia is a true piece of art. I am sure, though, that many will skip this album due to the extremely harsh production. I can only suggest not to pay too much attention to such values and focus on what can be found inside - thus Sielun Kadotuksen Sinfonia works like a Gnosis that can not be received without effort.