hierarch vs volkhv

hierarch

noun
  • One who has high and controlling authority in sacred things; the chief of a sacred order. 

  • A title of bishops in their role as ordinaries (arbiters of canon law) over their respective dioceses. 

volkhv

noun
  • a priest from Slavic neopaganism 

  • a pre-Christian priest from Slavic cultures 

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