Noise. A good definition of it.
Loud noise. A better definition.
This type of music is based entirely upon distortion and double bass drumming. Take this out and you only have weird inhuman throaty noises for vocals which try to convey political and social rebellion for the pseudo rebels who are actually unpopular loners and who want to "be different".
Also practices related to killing animals and burning religious books, which if seen objectively, have nothing to do with music whatsoever. Most of them also have something to do with satanic cults which is again a cover up for loners who cant get laid and blame god for it. And yeah, the people performing this noise have to put on make up. Nobody knows why.
Vocalist : Aaaaarrrrghh...laaarr...faaaaaaaaa....(incoherent throaty growling noises)
Black metal fan : What deep lyrics! What a melody!