mara vs night hag

mara

noun
  • A nightmare; a spectre or wraith-like creature in Germanic and particularly Scandinavian folklore; a female demon who torments people in sleep by crouching on their chests or stomachs, or by causing terrifying visions. 

  • Any malicious or evil spirit. 

  • Any caviid rodent of genus Dolichotis, common in the Patagonian steppes of Argentina. 

  • A type of god that prevents accomplishment or success. 

night hag

noun
  • a demon that gives rise to sleep paralysis 

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