Question: What musician performed on the album Witchkrieg and is also a member of Slayer?

Context paragraphs:
Terror (demo): Terror (also referred to as Evil Dead '94 because of the insert) is an independently released EP cassette by Evildead.  It contains demos that Evildead recorded in 1994 for the album that was intended to follow 1991's "The Underworld".  However, the new album was unfinished and never released as Evildead decided to call it quits.  All three songs from this EP were re-recorded by the band members' post-Evildead project Terror for their only album "Hijos de los Cometas" (1997).  This release marked the debut of singer Steve Nelson (who replaced founding member Phil Flores in 1993 and rejoined again in 2010) and the band's first with bassist Mel Sanchez since their 1989 debut "Annihilation of Civilization" as well as their only release with then-future and now-former Slayer drummer Jon Dette.  This would also be their final release with guitarist Dan Flores.

Jeff Hanneman: Jeffrey John "Jeff" Hanneman (January 31, 1964 – May 2, 2013) was an American musician, best known as a founding member of the American thrash metal band Slayer.  Hanneman contributed both lyrical and musical material to every Slayer album and wrote the songs "Raining Blood", "War Ensemble," "South of Heaven," "Seasons in the Abyss," and "Angel of Death," all of which have been played at almost every live Slayer performance after their respective compositions.  He had his own signature guitar, the ESP Jeff Hanneman Signature model.

Gasoline (band): Gasoline are a southern rock band and side project for former Pantera member Vinnie Paul.  They once included Dimebag Darrell, Thurber T. Mingus, and Stroker of Pumpjack.  Paul described the group's general theme as "booze and women."  The band has covered many artists including Pat Travers, Ted Nugent, Black Sabbath, W.A.S.P., Thin Lizzy, Quiet Riot, and Slayer, but have also performed original songs like "This Ain’t a Beer Belly, It’s a Gas Tank For My Love Machine" and "Get Drunk Now."  Paul claims the band formed as followed:

Repentless: Repentless is the twelfth studio album by American heavy metal band Slayer.  It was released on September 11, 2015, and is the first Slayer album to feature guitarist Gary Holt of Exodus and the first to feature drummer Paul Bostaph since 2001's "God Hates Us All".  "Repentless" is also Slayer's first album following the death of founding member Jeff Hanneman in 2013, and the band's first album to be released on Nuclear Blast.

Witchkrieg: Witchkrieg is the fifth full-length studio album by the Swedish thrash metal band Witchery, released on June 21, 2010, in Europe and June 29, 2010, in North America.  This album is their second on Century Media Records.  Like their previous album, "Don't Fear the Reaper", "Witchkrieg" was mixed by Tue Madsen at his Antfarm Studios.  "Witchkrieg" showcases an impressive line-up of guest musicians such as Andy LaRocque from King Diamond, Kerry King from the thrash band Slayer, Hank Shermann of Mercyful Fate, Lee Altus and Gary Holt from Exodus and Jim Durkin from Dark Angel.

Once More, with Feeling (Buffy soundtrack): Once More, with Feeling is a soundtrack album for the "Buffy the Vampire Slayer" episode of the same name.  The album features the original series cast performing the songs from the episode, as well as additional music from other popular episodes by regular composer Christophe Beck, including suites from season four episodes "Hush" and "Restless", as well as a score piece from season five episode "The Gift".  To finish of the album is a demo track of "Something to Sing About" performed by series creator and album songwriter Joss Whedon and his wife Kai Cole.  The art for the album, which is also used as cover for related items, such as the script book, the Region 2 DVD and the poster, is by popular comic book artist Adam Hughes.  The booklet includes liner notes by Whedon, the lyrics for the numbers, and various pictures from the episode.

60 Second Wipe Out: 60 Second Wipe Out is the third studio album by Atari Teenage Riot, before their hiatus.  This album showcased a newer sound, as Nic Endo had now became a member of the band.  Fewer samples were used.  Although heavily electronic in sound, the album was recorded on live instruments, that were then fed back and digitally altered.  It was mixed by Andy Wallace and features a variety of guest artists including Dino Cazares of Fear Factory, The Arsonists, and Kathleen Hanna.  The album was also issued as a double CD which featured a live show from Philadelphia.  Other versions also featured the B-side "Paranoid", and "No Remorse (I Wanna Die)" (featuring Slayer) from the "Spawn" soundtrack.

Composizioni: Composizioni is the second solo album by pianist Giovanni Allevi.  The musician performed "Piano Karate" at the 59th Festival della canzone italiana.

Gary Holt (musician): Gary Wayne Holt (born May 4, 1964) is an American guitarist from the San Francisco Bay Area.  He is a guitarist and the main songwriter for the American thrash metal band Exodus and is also a guitarist for the American thrash metal band Slayer, in which he took over duties for original guitarist Jeff Hanneman, who died in 2013.

Dave Lombardo: David "Dave" Lombardo (born February 16, 1965) is a three-time nominated, two time Grammy Award-winning Cuban American drummer, best known as a co-founding member of American thrash metal band Slayer.  Lombardo played drums on nine Slayer albums, including the 1986 album "Reign in Blood", which AllMusic called "groundbreaking", and the 2006 album "Christ Illusion", for which he received critical praise.  Lombardo's music career has spanned more than thirty years, during which he has been involved in the production of thirty-five commercial recordings covering a number of genres.  He has performed with numerous bands, including Grip Inc., Fantômas, Testament, Suicidal Tendencies, in addition to Slayer.  Lombardo is currently playing drums with Suicidal Tendencies. , Dead Cross and The Misfits.

Supporting paragraphs: Witchkrieg Gary Holt (musician)
Answer: Gary Holt