The Eternal Idol was Black Sabbath's thirteenth studio album, and the first of many to feature Sabbath vocalist Tony Martin.
Tony Iommi wrote "Nightmare" when he was asked to write the soundtrack for Nightmare on Elm Street. Tony wanted to be involved with the film, but his management held out for more money and the filmmakers backed off.
Iommi said of Tony Martin's lyrics on The Eternal Idol: "He assumed, oh, Black Sabbath, it's all about the Devil, so his lyrics were full of the Devil and Satan. It was too much in your face."
Kacey Musgraves originally offered "Follow Your Arrow" to her friend Katy Perry. However, Perry thought Musgraves should record the song herself as it seemed, "like something that you would totally say."