Mephistopheles vs Old Gentleman

Mephistopheles

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

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

Old Gentleman

name
  • The Devil. 

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