"Mercyful Fate" is a cover medley of songs from the band Mercyful Fate, and was originally recorded by Metallica. It appears in and is the longest song in Guitar Hero: Metallica, at eleven minutes and eighteen seconds, and it is the second longest song in the franchise, only exceeded by the live version of "Do You Feel Like We Do" by Peter Frampton in Guitar Hero 5. It is made up of the abbreviated versions of five Mercyful Fate songs:
- Satan's Fall
- Curse of the Pharaoh's
- Corpse Without Soul
- Into the Coven
The original song is found on Garage Inc., the Metallica-made cover album from 1998.