There are currently (at least) three bands named Behemoth.
1. Behemoth is an influential Polish blackened death metal band. Behemoth is considered to have played an important role in establishing the Polish extreme metal underground, alongside Vader and Sacrilegium. Until the early 2000's, the band played rather classic black metal with heathen lyrical content, but soon changed to occult and thelemic themes written by their leader, Nergal and the occultist and poet Krzysztof Azarewicz, first seen on their 1999 album, Satanica, regarded by some fans as a classic blackened death metal album.
This coincided with an increase in musical craftsmanship that allowed Behemoth to move beyond the black metal underground and to gain international recognition. With the 2004 release of Demigod, they had fully embraced modern death metal while retaining their own signature style characterized by the staggering drumwork of Inferno, multi-layered vocals and a middle-eastern influence compareable with Nile.
Their transition from black to death metal has made them "traitors," and "sell-outs" in the eyes of some of their old fans, but they have become popular of the modern death metal scene; Behemoth is often likened to other rising stars, such as Nile (with whom they have collaborated and toured).
Nergal: Vocals, Guitars
Orion: Bass Guitar, Backing Vocals
Seth: Studio/Session Guitars
2. A Swedish black metal band (Pre-In Aeternum), who released 2 demotapes in 1993/1994.
3. A Swedish heavy metal band, released the 7" Deathwings in 1982.