pale rider vs psychopomp

pale rider

noun
  • Death, the Grim Reaper or angel of death; and one of the Four Horsemen of the Apocalypse. 

psychopomp

noun
  • A spirit, deity, person, etc., who guides the souls of the dead to the afterlife. 

How often have the words pale rider and psychopomp occurred in a corpus of books? (source: Google Ngram Viewer )