guardian vs seraph

guardian

noun
  • A superior in a Franciscan monastery. 

  • A person legally responsible for a minor (in loco parentis). 

  • A person legally responsible for an incompetent person. 

  • Someone who guards, watches over, or protects. 

  • A major or final enemy; boss. 

seraph

noun
  • A six-winged angel; one of the highest choir or order of angels in Christian angelology, ranked above cherubim, and below God. They are the 5th-highest order of angels in Jewish angelology. A detailed description can be found at the beginning of Isaiah chapter 6. 

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