Although some authors argue that dark metal is a genre of heavy metal, there is a wide variety of opinions as to what elements, styles, or themes make metal dark.
Robert Palmer, rock critic for the New York Times, calls metal with themes of horror and violence dark, using the bands Megadeth, Anthrax, Slayer and Danzig as examples. In their books, Robert Walser and Richard D. Barnet agree that dark metal is music oriented towards the occult. Micah L. Issitt, Jeffrey Kaplan, Bryan Reesman, Joel MacIver, and Chuck Eddy all write that dark metal has gothic themes.
Many writers, including Ian Christe, music journalistChuck Eddy, Sara Pendergast, Tom Pendergast, Natalie J Purcell, Brian Reesman, Jeff Wagner, and Steven Wilson, find that there is a melancholy tone that distinguishes dark metal bands from their contemporaries. This tone has been variously described as "morose beauty", "broody", "beautiful and romantic", "sorrowful and haunting", "goth-tinged", and "gloomy".
^Rivadavia, Eduardo. "Biography of Insomnium". ...links to other, neighboring metallic subgenres like doom, melancholy, and dark metal.
^Sullivan, Jim (July 5, 1991). "Heavy metal tour sends a message -- loud and clear". The Boston Globe via HighBeam Research (subscription required). It was Metallica that opened the floodgates to this latest heavy metal subgenre, generally termed thrash metal, dark metal or death metal: fast, bone-crunching, hard rock played with ferocity, strewn with violent, bloody imagery.
^ abcdPalmer, Robert (Nov 4, 1990). "POP VIEW; Dark Metal: Not Just Smash And Thrash". New York Times. The horrific imagery so central to the lyrics of dark metal permeates popular culture, from horror films to illustrated "graphic" novels to the visceral new fiction of "splatter punks"...