What makes Opus IV by Abigor notable?

'Opus IV' is notable for its ambitious blending of black metal with progressive elements, receiving praise for its intricate arrangements. The album is often regarded as a pivotal release in the Austrian black metal scene, influencing subsequent bands with its experimental approach and atmospheric production. Released in 1996, 'Opus IV' was Abigor's third album, following their influential works 'Nachthymnen (From the Twilight Kingdom)' and 'Verwüstung / Invoke the Dark Age'. At this point, the band had solidified their reputation within the black metal scene, pushing further into avant-garde territory with complex compositions and thematic depth.