pale rider vs reaper

pale rider

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

reaper

noun
  • The recluse spider (Loxosceles and Sicarius spp.). 

  • One who reaps; a person employed to harvest crops from the fields by reaping. 

  • A machine used to harvest crops. 

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