Warthur
If Stian Aarstad was the star player on Dimmu Borgir's debut, demonstrating with his contributions that the band were taking black metal into an entirely new territory, then Stormblast is the album where the rest of the group up their game and overshadow him.
Set aside, for a moment, the plagiarism which necessitated the re-recording of the album in 2005 - getting his bandmates in trouble like that was a downright low thing for Stian to do, but I believe the band when they say they didn't realise he was ripping off other people's material and the offending track is a brief interlude anyway. The rest of the music on here is a compelling piece of early symphonic black metal which sets the precedent both for Dimmu Borgir's future career and also seems to have been an influence on the direction Cradle of Filth took at around this time.