Watch the For Whom the Half Step online guitar lesson by Chris Buono from 50 Metal Guitar Licks You MUST Know

String a series of half-steps together or group them in a disjunt manner and you have yourself chromaticism. When done right, chromatic passages can serve as the main ingredient in true metal fashion for myriad riff and/or lick environments. Though things can quickly get out of hand when potentially throwing around all twelve tones in the western system, sometimes simple descending chromatic evilness like what's heard at the beginning of Metallica's "For Whom the Bell Tolls" off Ride the Lightning is all you need.