alter ego vs enemy

alter ego

noun
  • Somebody's alternate personality or persona; another self. 

  • A very close and intimate friend. 

  • A corporation used by a person to conduct personal business in an attempt to shield himself or herself from personal liability, and which a court may penetrate by "piercing the corporate veil" to impose liability on the person when they commit fraud or injustice. 

enemy

noun
  • Someone who is hostile to, feels hatred towards, opposes the interests of, or intends injury to someone else. 

  • A hostile force or nation; a fighting member of such a force or nation. 

  • Something harmful or threatening to another 

  • Of, by, relating to, or belonging to an enemy. 

  • A non-player character that tries to harm the player. 

verb
  • To make an enemy of. 

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