Raining Blood
Raining Blood closes Reign in Blood and is the most perfectly constructed Slayer song — the track whose opening sequence (the thunderstorm fading in, the descending guitar figure, the abrupt arrival of the central riff) is one of the most immediately recognisable in metal. Every element earns its place: the intro creates anticipation rather than simply occupying time; the central riff delivers on that anticipation with proportional force; and the song's escalation toward the final section arrives with the inevitability of a storm breaking.
Jeff Hanneman wrote it. The falling tremolo figure after the opening thunderstorm — the specific atonal descending line that announces the riff — is one of the great compositional decisions in extreme metal, and the way the full riff arrives after it is the most satisfying single moment of construction in the Slayer catalogue. It is the last track on the most important extreme metal album ever made, and it earns that position.
Raining Blood is about a fallen angel's return to vengeance — the narrator exiled from the domain where they belong, returning to exact retribution on those responsible for the exile. The imagery (tornadoes of pain, trapped in purgatory, a god of thunder rising from the ground) draws on the Miltonic fallen-angel tradition. The rain of blood is simultaneously literal (the violence of the return) and symbolic (the cost of restoration). Hanneman's lyric is more structurally coherent than the surrounding Reign in Blood material.