1: Used to define either a metal head or a band thats either death or black metal (Ussually black metal though). Basically to put it short, Metalheads that are into the most extreme forms of metal (like yours truly), and bands that play extreme forms of metal (Immortal, Cannibal Corpse, Emperor, Morbid Angel, Mayhem, Entombed, etc.).
2: Used sarcastically against mallcore kiddies who think ACTING evil is cool. They ussually say racist, hateful and satanist things, but they probably dont even knjow or believe what they say, they just say it to look and act KVLT so real metalheads accept them.
(Metalhead)Look at that guy with spikes covering his forearms, a bullet belt and a shirt of Marduk, that guy's a black metal KVLTist, and that guy next to him with longhair, plain clothes and a shirt of Death is a death metal KVLTist
2: Look at that kid with the spikey hair, wallet chain, hot topic accesories, and slipknot shirt. He's a fucking mallcore kiddie wannabe-KVLT