After a few years of faithful service as Black Sabbath’s anti-Ozzy, elfin dynamo, Ronnie James Dio left to take front and center with his eponymous band’s 1982 debut, Holy Diver. But its follow-up two years later is where the band—featuring fellow Sabbath exile drummer Vinny Appice and future Whitesnake and Def Leppard guitarist Vivian Campbell—felt solidified. The title track is a classic of the starts-slow-then-kicks-in metal genre, and “Mystery” has a more traditional pop sensibility that sometimes gets forgotten amid Dio’s wizards-and-warlocks iconography.