"Don't Break the Oath" is the second studio album by the band Mercyful Fate, released in 1984. The record mixed heavy metal with progressive rock and was lyrically filled with Satan and the occult. Of course, it was also distinguished by King Diamond's theatrical vocals. Although this album became very influential to future black metal bands due to its lyrical content, the music itself is seen as traditionally heavy metal.
Mercyful Fate is a Danish heavy metal band that was formed in 1981 by vocalist King Diamond. They were part of the first wave of black metal music in the early 80s and are known as one of the most acclaimed bands in the European heavy metal scene. Mercyful Fate was the subject of controversy due to their Satanic imagery and lyrics. They are known for their theatrical falsetto vocals and occult themes.