myself vs themselves

myself

pron
  • Me, as direct or indirect object the speaker as the object of a verb or preposition, when the speaker is also the subject. 

  • Personally, for my part; used in apposition to I, sometimes for simple emphasis and sometimes with implicit exclusion of any others performing the activity described. 

  • Me (as the object of a verb or preposition). 

  • In my normal state of body or mind. 

  • my name is... 

themselves

pron
  • The reflexive case of they, the third-person singular personal pronoun. The single person previously mentioned, as the object of a verb or following a preposition (also used for emphasis). 

  • The reflexive case of they, the third-person plural personal pronoun. The group of people, animals, or objects previously mentioned, as the object of a verb or following a preposition (also used for emphasis). 

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