In 1936 Elizabeth Bowen had this to say about Jane Austen’s Mr Darcy:

“Returning again and again to Mr Darcy , one pays Jane Austen the compliment of deciding there was more to him than she knew. He has that cloudy outline important characters should have; does not seem to have been ‘created’ in the limited brain-bound sense so much as observed fleetingly out of the corner of an eye, recollected uncertainly, speculated upon.”

So characters in fiction take on a life of their own. In many cases they live on long after the author’s death, too. They achieve immortality, so to speak.