Question: What genre of music do Sonic Reign and Emperor fall under?

full_context: Document 1: Enslaved (band): Enslaved is a Norwegian extreme metal band formed by Ivar Bjørnson and Grutle Kjellson in Haugesund in June 1991. They are currently based in Bergen, Norway. Though the band's lineup has changed many times over the years, Bjørnson and Kjellson have been the sole constant members, and the lineup remained the same from 2004 to 2016. Following their 25th anniversary world tour, keyboardist/guitarist/vocalist Herbrand Larsen departed from the band after 12 years and six albums. He has since been replaced by Håkon Vinje.
Document 2: Blind Guardian: Blind Guardian is a German power metal band formed in the mid-1980s in Krefeld, West Germany. They are often credited as one of the seminal and most influential bands in the power metal and speed metal subgenres. Ten musicians have been a part of the band's line-up in its history, which has consisted of singer Hansi Kürsch, guitarists André Olbrich and Marcus Siepen, and drummer Frederik Ehmke since 2005.
Document 3: Emperor (band): Emperor is a Norwegian black metal band formed in 1991, regarded as highly influential by critics and emerging black metal bands. The group split up in 2001, but reunited from 2005 to 2007 for a few festival dates and brief US tours, and again reunited in 2013 to 2014. The group was founded by Ihsahn (guitar/vocal) and Samoth (then, drums).
Document 4: Sigurd Wongraven: Satyr (born Sigurd Wongraven on 28 November 1975) is the vocalist, lead and rhythm guitarist, bassist, and keyboardist for the Norwegian black metal band Satyricon. He was a founding member of Satyricon (although the band had been around for a short length of time as Eczema without him) and have so far released eight albums, two demos, and a live DVD. He has also contributed to other bands such as Darkthrone, Eibon, Storm, Thorns, Black Diamond Brigade and Wongraven. About black metal, he stated "It, black metal, doesn't necessarily have to be all satanic as long as it's dark." He has recently been endorsed by ESP Guitars.
Document 5: Black metal: Black metal is an extreme subgenre 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.
Document 6: Destruction (band): Destruction is a German thrash metal band. They have been referred to as one of the "Big 4" of the German thrash metal scene, the others being Kreator, Sodom and Tankard. Along with Venom (UK), Bathory (Sweden) and Celtic Frost (Switzerland), three of those four German bands (Tankard being the exception) are often credited with helping pioneer black metal, by containing several elements of what was to become the genre. Destruction was originally named Knight of Demon, but changed their name in 1984. For most of the 1990s, Destruction was not signed to a record label and was forced to self-produce their albums until they signed a contract with Nuclear Blast in the early 2000s.
Document 7: Darkthrone: Darkthrone is a Norwegian heavy metal band. It formed in 1986 as a death metal band under the name Black Death. In 1991, the band embraced a black metal style influenced by Bathory and Celtic Frost and became one of the leading bands in the Norwegian black metal scene. Their first three black metal albums—"A Blaze in the Northern Sky", "Under a Funeral Moon" and "Transilvanian Hunger" (sometimes dubbed the "Unholy Trinity") — are considered the peak of the band's career and to be among the most influential albums in the genre. For most of this time, Darkthrone has been a duo of Nocturno Culto and Fenriz, who have sought to remain outside the music mainstream. Since 2006, their work has strayed from the traditional black metal style and incorporated more elements of traditional heavy metal, speed metal and punk rock, being likened to Motörhead.
Document 8: Sonic Reign: Sonic Reign is a German black metal band consisting of two members: Ben (vox, strings) and Sebastian (drums). The band hails a very cold and modern variant of Black Metal influenced by bands such as Satyricon, Emperor and Thorns.
Document 9: Ihsahn: Ihsahn (born 10 October 1975 as Vegard Sverre Tveitan) is a Norwegian composer, multi-instrumentalist, and vocalist. He is best known for his work with Norwegian black metal band Emperor. He has appeared in Thou Shalt Suffer, played in Peccatum with his wife Ihriel (real name Heidi S. Tveitan), and now devotes himself to his solo albums.
Document 10: Mayhem (band): Mayhem is a Norwegian black metal band formed in 1984 in Oslo. They were one of the founders of the Norwegian black metal scene and their music has strongly influenced the black metal genre. Mayhem's early career was highly controversial, primarily due to their notorious live performances, the 1991 suicide of vocalist Per Yngve Ohlin ("Dead") and the 1993 murder of guitarist Øystein Aarseth ("Euronymous") by former member Varg Vikernes ("Count Grishnackh"), of Burzum.
Document 11: Ivar Bjørnson: Ivar Bjørnson (born November 27, 1977 in Etne) is a Norwegian composer/guitarist for the progressive black/viking metal band Enslaved. He is, along with Grutle Kjellson, one of only two founding members left in the current line-up, being only 13 years old at the time of the band's formation in 1991. Bjørnson and Grutle Kjellson performed in a death metal band called Phobia in 1989. The two decided that they wanted to form a new band in a more black metal style, and after discovering their shared fascination with Norse mythology, this set the groundwork for Enslaved. Beyond his duties on guitar, he writes almost all of the music for Enslaved as well as much of the lyrics. He has said that "When we started Enslaved we wanted to have the same level of commitment to something spiritual as our contemporaries in black metal [have with] the Satanic side. The dark destructive part of black metal didn't seem right because we didn't have any commitment to any Satanic ideology." He contributed keyboard/synth work to Borknagar's first three albums and synth/piano work on the Gorgoroth albums "Incipit Satan" and "Destroyer" under the name "Daimonion"; and also produced the first demo from black metal band Orcustus.
Document 12: Rammstein: Rammstein (] ) is a German industrial metal band, formed in 1994 in Berlin. Throughout its existence, Rammstein's six-man lineup has remained unchanged—lead guitarist Richard Z. Kruspe, bassist Oliver "Ollie" Riedel, drummer Christoph "Doom" Schneider, lead vocalist Till Lindemann, rhythm guitarist Paul H. Landers, and keyboardist Christian "Flake" Lorenz.
Document 13: Zyklon: Zyklon was a Norwegian blackened death metal band formed in 1998 by Samoth and Trym of Emperor, along with members of Myrkskog. Their style has been described as modern death metal with black and industrial undertones. After more than a 2-year hiatus, the band officially split up in January 2010.
Document 14: Euronymous: Øystein Aarseth (] ; 22 March 1968 – 10 August 1993), who went by the pseudonym Euronymous, was a Norwegian guitarist. Euronymous was a founder of and central figure in the early Norwegian black metal scene. He was a co-founder of the Norwegian black metal band Mayhem. He was also founder and owner of the extreme metal record label Deathlike Silence Productions and record shop Helvete.
Document 15: Satyricon (band): Satyricon is a Norwegian black metal band, formed in 1991 in Oslo. Satyr and Frost have been the band's core members since 1993. The band's first three albums typify the Norwegian black metal style. Since its fourth album in 1999, the band has strayed from this style and included elements of traditional heavy metal in their sound. Satyricon was the first Norwegian black metal band to join a multi-national record label (EMI).
ground_truth: Black Metal