Which band released the 1984 album 'Don't Break the Oath'?

Mercyful Fate released the 1984 album Don't Break the Oath.

It was the Danish band's second studio album and features vocalist King Diamond, whose high-register singing and theatrical stage persona became central to the group's identity. Guitarists Hank Shermann and Michael Denner supplied much of its distinctive melodic twin-guitar work.

The album's occult imagery and dramatic songwriting influenced later black metal, speed metal, and extreme metal musicians. Its sound remained rooted in traditional heavy metal while using unusual vocal melodies and complex guitar arrangements.

King Diamond is sometimes given as the answer because he later led a separate solo band under that name. However, Don't Break the Oath is a Mercyful Fate album, released before the original band split in 1985.