Mercyful Fate is a Danish heavy metal band from Copenhagen, formed in 1981 by vocalist King Diamond and guitarist Hank Shermann. Influenced by progressive rock and hard rock, with lyrics dealing with Satan and the occult, Mercyful Fate were part of the first wave of black metal in the early to mid-1980s. Many of the bands from this movement went on to influence later black metal musicians in the 1990s, particularly in Norway. Since the band's inception in 1981, Mercyful Fate have released seven studio albums, two extended plays and four compilations.

After several line-up changes and self-made demos, Mercyful Fate released their self-titled EP in 1982, with the line-up of King Diamond (vocals), Hank Shermann (guitar), Michael Denner (guitar), Timi Hansen (bass) and Kim Ruzz (drums). With this line-up the group recorded their first two studio albums (1983's Melissa and 1984's Don't Break the Oath), until 1985 when the band broke up due to musical differences. In 1993, four out of the five members of Mercyful Fate reunited to record the album In the Shadows, which was released the same year. During the 1990s, the band released four more studio albums and went through several line-up changes. Since 1999, Mercyful Fate have been on hiatus, but have reunited on occasion during the 2000s.