Avenged Sevenfold is known for its diverse rock sound and dramatic imagery in album covers and merchandise. The band emerged with a metalcore sound on their debut album "Sounding the Seventh Trumpet" and continued this sound through their second album "Waking the Fallen". However, the band's style had evolved by the group's third album and first major label release, "City of Evil", into a heavy metal and hard rock style. The band continued to explore new sounds with its self-titled release and enjoyed continued mainstream success before their drummer, James "The Rev" Sullivan, died in 2009. Despite his death, Avenged Sevenfold continued on with the help of drummer Mike Portnoy (Dream Theater), and released and toured in support of their fifth album "Nightmare" in 2010, which debuted on the top spot of the "Billboard" 200, their first number one debut.