Marrying chugging groove metal to vile thrash, Lamb of God emerged in the early '00s with a brutal alternative to post-grunge and nu-metal. On New American Gospel and Ashes of the Wake, the New Wave of American Heavy Metal act pour death-drenched grunts, hammering double-kicks, and locomotive riffs into finely crafted songs that unleash waves of suffocating nihilism, all while serving up killer hooks. Not afraid to challenge genre orthodoxy, on 2006's Sacrament the band incorporate plenty of metalcore breakdowns and speed metal tempos into their attack.