assignee vs emissary

assignee

noun
  • one who is appointed to act or speak in place of another; an agent 

  • one to whom rights or property is being transferred 

  • one to whom a thing is assigned 

emissary

noun
  • An agent sent on a mission to represent the interests of someone else. 

  • An underground channel by which the water of a lake escapes. 

  • A venous channel in the skull. 

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