Since coming together in 1999, Killswitch Engage have dedicated their career to boldly challenging metalcore's stylistic boundaries. They splice the genre's cornerstones—death growls, blast beats and savage breakdowns—with the lightning-quick precision of classic metal and the brooding heaviness of post-grunge. As the 2006 landmark As Daylight Dies demonstrates, their attack is downright impenetrable. Rousing melodic runs coil themselves around furiously chugging riffs and harsh yet clean vocal gymnastics, while the rhythm section flips between grinding grooves and propulsive beats.