This is the third in a series. Check out Part 1 (1980-84) and Part 2 (1985-1989)Â if you haven't read those first.
The gulf between Mayhem's seminal Deathcrush EP in 1987 and their first proper full length in 1994 was an industrious but often low-key period in the genre's ascendance. Much of the action was going on off-record and behind the scenes, notably in the basement of Mayhem guitarist Euronymous' infamous Helvete record shop. Though much would go on to be written about these nascent times (most notably in the notorious tome Lords of Chaos), as we'll see, for much of its early development the second wave of black metal would prove to be somewhat short on finished studio product. Note that this and following installments will be necessarily less comprehensive than previous entries in this series, as the sheer number of similar, minor bands arriving on the scene would make an encyclopedic round up overly exhausting.
– 1990 –
Many bands were still at the demo stage at the turn of the decade, with few record label options handling anything as raw and unvarnished as black metal at this point. One of the more promising were Sweden's Abruptum, originally begun by It, an important member of the Swedish Black Circle. It later left the band in 1996 but Abruptum continues as  a one-man band under the command of longtime collaborator Evil, although Evil has long since abandoned most semblances of actual black metal.
[youtube]https://www.youtube.com/watch?v=KQjkrjHiOrs[/youtube]
[youtube]https://www.youtube.com/watch?v=VYIQhlNK-2Y[/youtube]
Hailing from down in Belgium, Ancient Rites were still straddling the line between the forward-thinking black metal of their northern peers and first generation sloppy thrash at the time of their first demo, Dark Ritual. The raspy vocals and atmospheric guitar work proved them on the right track, however.
[youtube]https://www.youtube.com/watch?v=t3fC3SBrxhc[/youtube]
Bathory entered the 90's in an experimental phase. Their next album, Twilight of the Gods, arrived in 1991 but had  abandoned all pretexts of black metal in favor of  a clean, symphonic iteration of  Quorthon's developing Viking metal sound,  so for the purposes of this article this is the last we'll see of the group for now.
[youtube]https://www.youtube.com/watch?v=ZO2I41TlQAc&list=PLhp8teq5LbYnLvZgQHl8FmGGHy4W-K_wa&index=2[/youtube]
British Columbia seems like an odd place to find a true, "kvlt" BM band circa 1990, but Burnaby's own Blasphemy were actually ahead of the pack when they released their first official album, Fallen Angel of Doom, on Wild Rags. Aside from some decidedly death metal-sounding guitar solos the band were impressively ahead of their time in terms of capturing a sound that was still percolating in tape trader circles half a world away.
[youtube]https://www.youtube.com/watch?v=J6kh37y8B3M[/youtube]
Mayhem hadn't released anything since 1987's Deathcrush by 1990, and indeed the Freezing Moon/Carnage demo would be the last thing at all the band would release until the bootleg quality Live in Leipzig, which was recorded in 1990 and originally passed around as a demo tape by the band the next year, but would remain largely unavailable to  the public until it received a semi-official release in 1993. The latter, along with another bootleg quality archival release, Dawn of the Black Hearts, were put on the market in spite of their poor quality due to being some of the last surviving recordings of Dead before his 1991 suicide. "Freezing Moon" would be re-recorded for 1994's De Mysteriis Dom Sathanas with Attila Csihar on vocals.
[youtube]https://www.youtube.com/watch?v=rSHf81j_PQE[/youtube]
[youtube]https://www.youtube.com/watch?v=HoBBPKcvDx4[/youtube]
[youtube]https://www.youtube.com/watch?v=SNl8qar8Qk8[/youtube]
Old Funeral were really more of a straight up death metal band with BM-friendly vocals, but they're included here for posterity's sake as those vocals were provided on the Abduction of Limbs demo by none other than Abbath, later of Immortal and here going by the moniker Olve.
[youtube]https://www.youtube.com/watch?v=IVBpNI1qb3w[/youtube]
While not the most brutal of early black metal bands, Czech  group Root can certainly stake a claim for being one of the first. Formed in 1987, the band had already released four demos by 1990. That  year's Zjeveni represented an early and interesting stab at non-Scandinavian black metal, with frontman Big Boss acknowledging the isolation the band toiled in, with very limited distribution of official releases and no real tape-trading circles to speak of. The end result was something incapable of outgunning the sheer ferocity of their northern brethren but adding another take on the genre to the growing sphere of influences.
[youtube]https://www.youtube.com/watch?v=kEm7unMpkUk[/youtube]
Japan's Sabbat are one of those divisive bands who either score high on people's list of Earliest Black Metal Bands Ever or are just steadfastly ignored altogether.  That has a lot to do with the fact that – even though the band debuted with a self titled EP as far back as 1985 – by 1990 they still just as often sounded like Motorhead as Bathory, but I mean hell… that never stopped Venom from reaping massive street cred for doing the same thing, right?
[youtube]https://www.youtube.com/watch?v=NgFfclTGb3o[/youtube]
Sabbat weren't the only thrash-inflected black metal game in Japan in 1990. Sigh would go on to vastly eclipse the former in popularity over the years with their  experimental blend of black metal with every prog trope they could get their hands on (even the silly Zappa-esque stuff), but on the Desolations demo they were clearly still getting their feet wet.
[youtube]https://www.youtube.com/watch?v=rKwF6Pyndxs[/youtube]