Prince of Darkness vs diablo

Prince of Darkness

name

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

  • Satan; the Devil. 

  • A particularly evil person. 

diablo

noun

  • the devil 

adj

  • diable, flavoured with hot spices 

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