blood relative vs scion

blood relative

noun
  • A person who is related to another through a common ancestor, and not merely by marriage or adoption. 

scion

noun
  • A descendant, especially a first-generation descendant of a distinguished family. 

  • A detached shoot or twig containing buds from a woody plant, used in grafting; a shoot or twig in a general sense. 

  • A guardian. 

  • The heir to a throne. 

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