Question: Which is a heavy metal band, Gary Braver or System of a Down?
Context: Patrick Bruders is an American musician, best known as the current bassist for heavy metal supergroup Down, the former bassist of the blackened death metal band Goatwhore from 1997 to 2004, and the former bassist for the seminal sludge metal band Crowbar from 2005 until 2013.  In 2008 he joined Eyehategod side project Outlaw Order and began live bass duties for the band, but has since parted ways with the group.  He began touring as live bassist with heavy metal supergroup Down in early 2011, replacing former bassist Rex Brown, before being added as a permanent member, performing bass duties live and in the studio.  Bruders is also a member of the New Orleans-based crust punk band Gasmiasma, Austin-based country band Pure Luck, and joined legendary doom metal band Saint Vitus for their performance at the Hammer of Doom music festival in Würzburg, Germany. Gary Goshgarian known by his pen name Gary Braver is an English professor at Northeastern University (Boston), United States, where he teaches courses in science fiction, modern bestsellers, horror fiction, and fiction writing. 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. Acrassicauda is an American-based Iraqi heavy metal band formed in 2001.  It is often credited as being the first heavy metal group to emerge from Iraq.  The original band consisted of three Arab members and one Assyrian (Tony Aziz Yaqoo).  The band formed and played concerts under the regime of Saddam Hussein.  It became well known outside of the local Iraqi metal scene after Vice magazine did a profile of the band.  It received even greater coverage when it was profiled in a feature-length documentary about the band and its troubles in Iraq called "Heavy Metal in Baghdad".  The band's first album was released on March 9, 2010. Heavy metal bass is the use of the bass guitar (also called "electric bass") in the rock music genres of heavy metal and hard rock.  The bassist is part of the rhythm section in a heavy metal band, along with the drummer, rhythm guitarist and, in some bands, a keyboard player.  The prominent role of the bass is key to the metal sound, and the interplay of bass and distorted electric guitar is a central element of metal.  The bass guitar provides the low-end sound crucial to making the music "heavy".  The bass plays a "...more important role in heavy metal than in any other genre of rock." The History of Heavy Metal ("Hårdrockens historia") is a Swedish 2001 documentary movie made for TV spanning through the timeline of heavy metal music.  It starts with the roots of heavy metal and ends with the metal of present times.  Through interviews and archive material, the movie tries to give answers on many questions, including "which was the first heavy metal band?" .  It was produced by Malik Bendjelloul and edited by Mikael Björnsson and Johan Larsson for Barracuda Film & TV. System of a Down, sometimes shortened to System and abbreviated as SOAD, is an Armenian-American heavy metal band from Glendale, California, formed in 1994.  The band currently consists of Serj Tankian (lead vocals, keyboards), Daron Malakian (vocals, guitar), Shavo Odadjian (bass, backing vocals) and John Dolmayan (drums). Obús is a Spanish heavy metal band created in Madrid in the early 80s.  They stood out because they took the risk of making a big spectacle in their concerts in order to reach to the level of other international heavy metal bands.  In addition, the lyrics they write and the feelings they transmit connect with the people that follow them.  As they said in an interview: "All our songs , some more and some less, have a meaning".  Far away from renouncing to their genre, they have always claimed that they were a heavy metal band and they even wrote a song about this genre in their first LP called"Dosis de Heavy Metal". In 2012, because of their 30th anniversary, they did a Tour around Spain. Massacration is a Brazilian satirical heavy metal band, self-proclaimed "greatest and most classic heavy metal band, the inspiration behind most heavy bands since 1985, whose members' hairdos and posing influenced the whole heavy metal culture".  The classical line-up consists of Detonator (vocal, Bruno Sutter), Blondie Hammet (lead guitar, Fausto Fanti), Metal Avenger (bass guitar, Marco Antônio Alves), Jimmy "The Hammer" (drums, Felipe Torres) and Headmaster (rhythm guitar, Adriano Pereira). Metalucifer is a Japanese heavy metal band, formed by Gezolucifer (of Sabbat) in 1995.  Adopting the musical style of early NWOBHM and building upon it, they achieved underground celebrity, especially in Scandinavia.  Their pure heavy metal approach, and their unadulterated use of the words "Heavy Metal" in song titles has gained them fame, as their music strives to capture the essence of what they think "heavy metal" should be.
Answer: System of a Down