IRON MAIDEN - PURGATORY (7 INCH) - Vinyl, 7", 45 RPM, Single, Reissue Released: October 2014 Purgatory" is Iron Maiden's fifth single, released on 15 June 1981, and would be their last with singer Paul Di'Anno. It served as the second single from Killers. Genghis Khan - This is an instrumental song that expresses musically the fear, terror, apprehension, and feeling of being overwhelmed. It also "describes" the army's military power. Genghis Khan was a warrior who led the Mongolian empire.