Roots of Altars of Madness

Possessed is an American death metal band, originally formed in 1982 in the San Francisco Bay Area. Noted for their fast style of playing and Jeff Becerra's growled vocals, they are often called the first band in the death metal genre, and paved the way for the 1980s Bay Area thrash metal scene, along with Metallica, Exodus, Testament and Death Angel. The band is also notable for featuring then-teenage guitarist Larry LaLonde, who went on to join Primus.

Slayer is an American thrash metal band from Huntington Park, California, formed in 1981 by guitarists Kerry King and Jeff Hanneman, drummer Dave Lombardo and vocalist/bassist Tom Araya. Slayer's fast and aggressive musical style made them one of the "big four" bands of thrash metal, alongside Metallica, Megadeth, and Anthrax. Slayer's current lineup comprises King, Araya, drummer Paul Bostaph, and guitarist Gary Holt, who initially joined as a touring musician in 2011 before joining the band permanently after Hanneman's death in 2013; the drummer Jon Dette is a former member of the band.