Apollyon vs Prince of Darkness

Apollyon

name
  • The destroying angel of the abyss, the undoer or disintegrator. 

Prince of Darkness

name
  • Used other than figuratively or idiomatically: see prince, darkness. 

  • Satan; the Devil. 

  • A particularly evil person. 

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