Black metal is an extreme subgenre and subculture of heavy metal music. Common traits include fast tempos, a shrieking vocal style, heavily distorted guitars played with tremolo picking, raw (lo-fi) recording, unconventional song structures, and an emphasis on atmosphere. Artists often appear in corpse paint and adopt pseudonyms.
During the 1980s, several thrash and death metal bands formed a prototype for black metal. This so-called first wave included bands such as Venom, Bathory, Mercyful Fate, Hellhammer and Celtic Frost. A second wave arose in the early 1990s, spearheaded by Norwegian bands such as Mayhem, Darkthrone, Burzum, Immortal, Emperor and Gorgoroth. The early Norwegian black metal scene developed the style of their forebears into a distinct genre. Norwegian-inspired black metal scenes emerged throughout Europe and North America, although some other scenes developed their own styles independently. Some prominent Swedish bands spawned during this second wave, such as Marduk, Nifelheim and Dark Funeral.
Initially a synonym for "Satanic metal," black metal is often met with hostility from mainstream culture, due to the actions and ideologies associated with it. Many artists express extreme anti-Christian and misanthropic views, advocating various forms of Satanism or ethnic paganism. In the 1990s, members of the scene were responsible for a spate of church burnings and murders. There is also a small neo-Nazi movement within black metal, although it has been shunned by many prominent artists. Generally, black metal strives to be inaccessible to the mainstream and those who are not committed.
Regarding the sound of black metal, there are two conflicting groups within the genre: "those that stay true to the genre's roots, and those that introduce progressive elements". The former believe that the music should always be minimalist – performed only with the standard guitar-bass-drums setup and recorded in a low fidelity style. One supporter of this train of thought is Blake Judd of Nachtmystium, who has rejected labeling his band black metal for its departure from the genre's typical sound. Snorre Ruch of Thorns, on the other hand, has said that modern black metal is "too narrow" and believes that this was "not the idea at the beginning".
Since the 1990s, different styles of black metal have emerged and some have melded Norwegian-style black metal with other genres.
- Ambient black metal is a subgenre of black metal which relies on heavy incorporation of atmospheric, sometimes dreamy textures, therefore moving into a less aggressive direction. It often features synthesizers or classical instrumentation, typically for melody or ethereal "shimmering" over the wall of sound provided by the guitars. The music is usually slow to mid paced with rare blast beat usage, without any abrupt changes and generally features slowly developing, sometimes repetitive melodies and riffs, which separate it from other black metal styles. Subject matter usually concerns nature, folklore, mythology, and personal introspection. Artists include Agalloch and Wolves in the Throne Room.
- Black 'n' roll is a style of black metal that incorporates elements from 1970's hard rock and glam rock, as well as rock and roll music. Examples of black 'n' roll bands include Kvelertak, Vreid and Khold. Bands such as Satyricon, Darkthrone, Nachtmystium, Nidingr, Craft and Sarke also experimented with the genre.
- Black-doom (or blackened doom) melds doom metal with black metal. Examples of blackened doom bands are Barathrum, Forgotten Tomb and Woods of Ypres.
- Blackened death metal melds death metal with black metal. Examples of blackened death metal bands are Belphegor, Behemoth, Akercocke and Sacramentum.
- Blackgaze (or post-black metal) incorporates heavier elements common of black metal such as blast beat drumming and high-pitched screamed vocals with melodic elements and heavily distorted guitar styles typically associated with shoegazing. It is associated with bands such as Deafheaven, Numenorean and Alcest.
- Pagan metal is metal music with lyrics and imagery that focus on paganism. The Norwegian band In the Woods... was one of the first bands commonly viewed as pagan metal. In the mid-1990s, Irish bands such as Cruachan and Primordial began to combine black metal with Irish folk music.
- Symphonic black metal is a style of black metal that incorporates symphonic and orchestral elements. This may include the usage of instruments found in symphony orchestras (piano, violin, cello, flute and keyboards), "clean" or operatic vocals and guitars with less distortion.
- Viking metal is characterized by a common lyrical and thematic focus on Norse mythology, Norse paganism, and the Viking Age. With origins in black metal and Nordic folk music, it is typically manifested as Nordic folk-influenced black metal. Some common traits include a slow paced and heavy riffing style, anthemic choruses, use of both clean and harsh vocals, a frequent reliance on folk instrumentation, and, often, the use of keyboards for atmospheric effect. Viking metal developed in the 1980s through the mid-1990s as a rejection of Satanism and the occult, instead embracing the Vikings and paganism as the leaders of opposition to Christianity. It is similar, in lyrics, sound, and thematic imagery, to pagan metal, but pagan metal has a broader mythological focus and utilizes folk instrumentation more extensively. The origin of Viking metal can be traced to the albums Blood Fire Death (1988) and Hammerheart (1990) by Swedish band Bathory. Enslaved, Burzum, Emperor, Storm and Falkenbach helped further develop the genre in the early through mid-1990s. Though originated from black metal, some death metal bands such as Unleashed and Amon Amarth are included in the style.
- War metal, also known as war black metal or bestial black metal, is an aggressive, cacophonous and chaotic black metal style, described by Rock Hard journalist Wolf-Rüdiger Mühlmann as "rabid" and "hammering". Important influences include first wave band Sodom, first wave/death metal band Possessed as well as old grindcore, black and death metal bands like Repulsion, Autopsy, Sarcófago and the first two Sepultura releases. War metal bands include Blasphemy, Archgoat, Impiety, In Battle, Revenge and Zyklon-B.