custodian vs guardian angel

custodian

noun
  • A person entrusted with the custody or care of something or someone; a caretaker or keeper. 

  • a janitor; a cleaner 

guardian angel

noun
  • A tutelary angel watching over a particular person in monotheistic contexts. 

  • A person who watches over another. 

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