angel of death vs eternal sleep

angel of death

noun
  • Death, one of the Four Horsemen of the Apocalypse. 

  • A type of serial killer who is employed as a caregiver and kills people under their care. 

  • A shinigami. 

  • The Grim Reaper. 

  • An angel which attends to death, collecting souls at death, ending life at the appointed time of death. 

  • Azrael. 

eternal sleep

noun
  • Death 

  • A magical state of suspended animation, a state of ageless, deathless, everlasting sleep. Well-known examples are Endymion, (the lover of the Greek moon goddess, Selene), and the princess from Sleeping Beauty. 

How often have the words angel of death and eternal sleep occurred in a corpus of books? (source: Google Ngram Viewer )