Antestor are known as one of the brightest lights within the Christian black metal scene, but they were not always so - in their earlier days, they were far more of a doom/death act than a black metal one. Before the Nordic thundering of "The Forsaken", before the melancholic dirges of "The Return of the Black Death", there was this battle-axe of an album.
Funny thing is, though Antestor's sound has varied over the years, the same basic feeling and atmosphere remains, though the style changes. Antestor's "sorrow metal" description describes the sound generated over the course of their career rather well - the melancholy, pounding doom riffs, anguished vocals, and classical piano bits are all accounted for on pretty much every release.
Regardless, consider "Martyrium" to be Antestor's most death metal sounding release. Where their early recordings had a sound very reminiscent of My Dying Bride's "As the Flower Withers", this disc blends that particular sound with the more grindish elements of classic Obituary and some black metal shrieks here and there. All in all, it's quite a varied album.
The guitars grind and pulverize, and Martyr pulls off some amazing vocals that vary from death metal growls to all-out high-pitched black metal screams. The doomy atmosphere is kept intact for most of the album however - rarely do the band ever break out into a gallop; Antestor prefers to crush, pound, and bury its listener rather than flay them alive.
Track-wise, there is a lot of variety here. "Spiritual Disease" and "Thoughts" are the most black metal like songs on this album, though "Spiritual Disease" descends into Incantation like doom/death at times. "Inmost Fear" sees the band at their most like My Dying Bride, and "Searching" is the band playing full-strength death metal (crank this track, you'll be thankful you did).
Overall, it's an excellent and underrated album - it may not be as grim or majestic sounding as later albums, but in its own right, it dominates.