Question: The singer for the band Vertex, is best known as the founder, singer and songwriter of what heavy metal band?

Context paragraphs:
Joey Jordison: Nathan Jonas "Joey" Jordison (born April 26, 1975), is an American musician, songwriter, record producer and multi-instrumentalist, best known for his work as the former drummer and co-songwriter for the American heavy metal band Slipknot as well as guitarist in the American horror punk band Murderdolls.  Jordison played in Slipknot since their formation in 1995 until his departure from the band in December 2013.  He was the drummer and founder of the American heavy metal band Scar the Martyr which formed in 2013 and disbanded in 2016.  He grew up in Waukee, Iowa with his parents and two sisters, and was given his first drum kit at the age of 8.  He performed in several bands until joining in the summer of 1995 with the group The Pale Ones, which would later change their name to Slipknot.  Of Slipknot's nine-member lineup which lasted from 1999–2010, Joey was the third to join the band.

Vertex (band): Vertex was a band formed in 1995 featuring singer Stephen Pearcy (Ratt, Arcade, Vicious Delite, Nitronic), guitarist Al Pitrelli (Danger Danger, Hotshot, Alice Cooper, Asia, Savatage, Megadeth, Trans-Siberian Orchestra), and drummer Hiro Kuretani (WXXI, Trancentral Station).

Acrassicauda: 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.

Stephen Pearcy: Stephen Eric Pearcy (born July 3, 1956), known as Stephen Pearcy, is an American musician.  He is best known as the founder, singer, and songwriter of the heavy metal band Ratt.  He has also been in the bands Firedome, Crystal Pystal, Arcade, Vicious Delite, Vertex.  He has also recorded four records as a solo artist.

Patrick Bruders: 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.

Jack Starr: Jack Starr is a heavy metal and blues guitarist and songwriter born of a French mother and American father.  He learned to play guitar by ear, copying the riffs of R&B records.  His first semi-professional band was Les Variations in France with future members of Trust.  In the U.S. Starr emerged on the rock and metal scene in 1981, forming, together with Joey Ayvazian, David DeFeis and Joe O’Rielly, the first incarnation of the heavy metal band Virgin Steele.  The new band was selected in 1982 by Mike Varney of Shrapnel Records to appear on the label's compilation album "U.S. Metal Volume 2".  The song Starr sent in for the compilation was "Children of the Storm".  After only two albums, "Virgin Steele" of 1981 and "Guardians of the Flame" of 1982, Starr left Virgin Steele in 1983 because of musical differences with the band’s front man and other main songwriter David DeFeis.

Dan Spitz: Daniel Alan Spitz (born January 28, 1963) is an American musician and watchmaker best known for his work as the lead guitarist, principal songwriter and co-producer of the American heavy metal band Anthrax from 1983 to 1995 and from 2005 to 2008.  With Anthrax, Spitz was nominated for three Grammy awards and has been awarded platinum and multiple platinum RIAA certified albums for his entire Anthrax catalog of work.  Dan Spitz is the first heavy metal songwriter to have his music playing on two planets.  NASA chose his song alongside only 9 other artists such as Frank Sinatra and the Beatles to be played on the Lunar Rover Curiosity making him the first heavy metal artist to have a top 10 charting song on two planets.  Spitz also founded the Christian music group Red Lamb alongside Dave Mustaine of Megadeth as his writing partner, the first to bring autism awareness into any genre of music or music video.

Halford (band): Halford is an American heavy metal band formed in 1999 by British singer Rob Halford, who is best known as the lead vocalist for Judas Priest.  Halford formed the band to return to his heavy metal roots.  His two previous projects were a "street metal"-style band called Fight and the industrial metal band 2wo.

Kurdt Vanderhoof: Kurdt Vanderhoof (born June 28, 1961) is an American guitarist, best known as the lead guitarist and founding member of the American heavy metal band Metal Church.  As early as 1976, in Aberdeen, Vanderhoof was ardently networking with local musicians and had formed a band called Tyr, which included Kirk Arrington on drums and Vanderhoof on rhythm guitar.  In 1978 Vanderhoof joined Seattle hardcore punk band The Lewd adopting the stage name "Blobbo" on bass guitar, switching instruments to guitar the following year.  The Lewd relocated from Seattle to San Francisco in 1980.  Following Vanderhoof's departure from The Lewd he formed Metal Church, named after a nickname given to his San Francisco apartment.  Vanderhoof moved back to his hometown, Aberdeen, Washington, with a vinyl single of Trash Can Baby as proof of his interlude with the Lewd.  In the summer of 1982, he formed a heavy metal cover band named Shrapnel.  It consisted of Tom Weber on drums, Duke Erickson on bass (both from Hoquiam), Mike Murphey ("muff", from Montesano) and a guitar player Vanderhoof had jammed with in high school(Aberdeen).  Shrapnel played four events to warm up, including a frat party at Pacific Lutheran University, after which the other guitar player quit, having had a religious experience, unwilling to cover The Number of The Beast by Iron Maiden.  His part was replaced by Craig Wells of Aberdeen, and Tom was eventually replaced by Kirk Arrington (also from Hoquiam) on drums.  When Mike Murphy left the band, they recruited David Wayne for vocal duties.  By 1983, Shrapnel had renamed itself to Vanderhoof's original band name, Metal Church.

Robert Trujillo: Roberto Agustin Trujillo (] ; born October 23, 1964) is an American musician and songwriter best known as the current bassist of the heavy metal band Metallica, a position he has held since 2003.  He was also a member of crossover thrash metal band Suicidal Tendencies, funk metal supergroup Infectious Grooves, and heavy metal band Black Label Society, and has worked with Jerry Cantrell and Ozzy Osbourne.

Supporting paragraphs: Vertex (band) Stephen Pearcy
Answer: Ratt