Warthur
Although some other so-called "first wave black metal" bands like of Venom and Mercyful Fate had released material earlier, both of those bands really existed more as proto-thrash units than as black metal groups; Hellhammer, conversely, have a much better claim for being the progenitors of black metal with this sick demo material (often combined with Death Fiend, which was recorded at the same time), which features bestial vocals and furious, driving rhythms underneath a sea of guitar sludge. As with Venom's debut, the production values are terrible - however, unlike with Venom, underneath the fuzzy production the band are clearly doing something truly unprecedented in metal at that time.