They were inspired by the early fast-playing bands such as Kreator, Sodom, Destruction and Bathory.

[1] First they did some local gigs as "Obsessed" and "Black Mass" but changed their name to Merciless in early 1987.

A demo was recorded titled Behind the Black Door, which led to the replacement of Kåle by Rogga in early 1988.

In 1999, their debut album was re-issued by Osmose Productions, which eventually led to the reinstallment of the band.

In May 2002, they entered the studio to record the successor to their 1994 album, simply named Merciless.