Behemoth is an influential Polish blackened death metal band. They are considered to have played one of the most important roles in establishing the Polish extreme metal underground, alongside Vader, Graveland, and Sacrilegium. Until the early 2000s, the band played classic black metal with heathen lyrical content, but soon changed to that of occult and thelemic themes written by their lead vocalist Nergal and Krzysztof Azarewicz.