The contrasts that envelop Vintersorg are as deep and ironic as anything in the Swedish death metal genre.

The Borknagar vocalist's fascination with nature's most technical and elusive details is combined with Nordic folk influences to make a strange conceptual structure.

On early releases, the overly ambitious material is burdensome.

But as his career progressed, Vintersorg and his two-man eponymous band (including guitarist Matthias Klinkmann) hit a nice artistic stride.

On the group's 2002 release, Visions From the Spiral Generator, Vintersorg's pattern of increased musical complexity holds up, but for the first time the performances and production are up to the challenge.

The vocals are superior to those of prior releases like Odemarkens Son, and everything about Visions From the Spiral Generator is just larger and more refined.

There are better folk-influenced, progressive, Swedish death metal artists (Opeth, most notably), but Vintersorg deserves credit for continually updating and improving their specialized formula.