the 1990s), several thrash metal established bands started to expand their sound by adding elements and influences from the groove metal genre. Anthrax, who had recently replaced Joey Belladonna with John Bush as their singer, began stepping away from their previously established thrash metal formula to a more accessible alternative/groove metal approach for the remainder of their 1990s output, starting with and including Sound of White Noise (1993). Sacred Reich, Overkill, Coroner, Prong, Testament, and Forbidden followed this trend with their respective albums Independent, I Hear Black, Grin, Cleansing, Low, and Distortion. Sepultura's 1993 album Chaos A.D. also marked the beginning of their transition away from death/thrash metal to groove metal which had influenced then-up-and-coming bands like Korn, who reciprocally became the inspiration behind the nu metal style of the band's next album Roots (1996). Roots would influence a generation of bands from Linkin Park to Slipknot, which during the 1990s meant the replacement of death, thrash, and speed, by nu metal and metalcore as popular epicenters of the hardest metal scene. Staying away from this new commercial mainstream of groove metal, metalcore, and especially nu metal, the second wave of black metal emerged as an opposed underground music scene, initially in Norway. This crop of new bands differenced themselves from the "first wave" by totally distilling black metal from the combined origins with thrash metal, but they preserved from all these sub-genres the emphasis on atmosphere over rhythm. As further extreme metal genres came to prominence in the 1990s (industrial metal, death metal, and black metal each finding their own fanbase), the heavy metal "family tree" soon found itself blending aesthetics and styles. For example, bands with all the musical traits of thrash metal began using death growls, a vocal style borrowed from death metal, while black metal bands often utilized the airy feel of synthesizers, popularized in industrial metal. Today the placing of bands within distinct sub-genres remains a source of contention for heavy metal fans, however, little debate resides over the fact that thrash metal is the sole proprietor of its respective spin-offs. 2000s and 2010s Many 1980s-era thrash bands who split or were inactive during the 1990s – such as Dark Angel, Death Angel, Nuclear Assault, and Forbidden – reunited in the 2000s. Notable bands returned to their roots with releases such as Kreator's Violent Revolution (2001), Metallica's Death Magnetic (2008), Megadeth's Endgame (2009), Slayer's World