Until the Light Takes us is a decent enough documentary, and i always appreciate whatever Fenriz has to say. and i'm not surprised he likes electronic music, a lot of the black metal artists from that time listened to stuff like 70's Kraftwerk and Tangerine Dream (see: Mayhem using a composition by Tangerine Dream for their intro to Deathcrush, Beherit using electronic interludes on their black metal stuff and going full on electronic in the middle of their career, etc).
i've never seen a documentary or read anything that's supposed to be some kind of metal history that left me truly satisfied, though. a lot of the "renowned" ones like Get Thrashed or Global Metal are particularly bad. though i'm interested in Daniel Ekeroth's book on Swedish Death Metal, and i read Lords of Chaos awhile ago and thought it was alright.
speaking of Fenriz and documentaries, it isn't really a documentary, but anyone interested in the history of black metal in terms of the bands and not the drama around it should check out
this video. 30 minute video covering 90% of black metal history, from the 80's stuff (Venom, Bathory, bestial Brazilian bands like Sarcofago and such) to around the mid 90's i think, it's been awhile since i've watched it. he leaves out stuff like Von and Blasphemy and it's perhaps more biased towards the Norwegian stuff once you get into the 90's, but it's a decent enough watch for 30 minutes. unfortunately the whole thing isn't on youtube as the whole thing is 50 minutes, but that 30 minute clip covers a lot. i think it might be an extra from Until The Light Takes Us, actually.
if that doesn't leave you satisfied enough he did a compilation album with a bunch of bands that inspired black metal like Destruction etc, as well as a few new bands that are keeping the style alive like Aura Noir.
tl;dr FENRIZ
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