deathlessness vs spiritual world

deathlessness

noun
  • The state of being deathless; eternity; immortality. 

spiritual world

noun
  • The afterlife. 

  • A metaphysical plane of existence parallel to the material world and occupied by spirits and other unearthly forces. 

How often have the words deathlessness and spiritual world occurred in a corpus of books? (source: Google Ngram Viewer )