Finnish Black Doom (early) / Black Metal (later)
The band formed as Darkfeast, before changing their name to Barathrum later in the same year (1990).
The first letter from each full-length album in chronological order spell out "Heil Sova."
BARATHRUM items we have:
The Tractatus De Hereticis Et Sortilegiis
Unholy Finnish Black Horror Union
Threshold of the Usurper LS S-Size
Threshold of the Usurper TS S-Size