Lindesberg based Death Metal. The band was created during 1997 by the guitar pairing of Matte Andersson and Robban Kanto with drummer Andreas Vallette. However, the latter two members soon exited leaving Andersson to rebuild the band, recruiting Pär Svensson. Still as a duo RELENTLESS cut the demo 'Pestilence Of The Undead', after which Gabbe Sternberg was introduced as second guitarist and former member Robban Kanto made a return as stand in bass player before switching to guitar.

RELENTLESS issued the cassette release 'Experiment In Excrement' in early 2000. Andreas Jansson of IN NOMINE repute then took the bass position. A further line-up shuffle found RELENTLESS as a trio comprising Andersson, Svensson and bass guitarist Oskar Pålsson.

Oskar Pålsson co-forged COLDWORKER in 2006, an alliance with NECRONY and NASUM drummer Anders Jakobson, RUIN and CHAIN OF HATE guitarist Anders Bertilsson, PHOBOS singer Joel Fornbrandt plus André Alvinzi of CARNAL GRIEF as second guitarist.