The Incarnation of Sathanas is a demo released by Ohura-Mazdo that was self-released in 1992. The album is mostly doom metal, but there is also some raw black metal parts. The album apparently has vocals but it sounds instrumental due to the poor recording quality.
As the name implies doom metal sounds like impending doom. Long notes and is slower compared to other genres of metal (but not as slow as drone doom). The tracks have a great and ominous vibe to them. The album also has some cool tracks that aren’t metal for the intro and outro.
Listen to it here~