Heavy metal, at least as God and Black Sabbath originally intended it, exists to help listeners confront or at least come to terms with their demons. Songs like “Black Sabbath” and “Sabbath Bloody Sabbath” were mini horror movies, sure, but the narrator was never the monster; it was someone who’d already seen too much, the old man warning foolish teens not to go to the summer camp because there’s a murderous psycho lurking in the woods. Somewhere along the way, though, headbangers started