King of Hell vs Mephistopheles

King of Hell

Mephistopheles

noun
  • A fiendish person, especially one who tricks someone into following a destructive or disastrous course of action; a tempter. 

name
  • The Devil to whom Faust sold his soul in the legend. 

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