Jack Napier is, of course, the name of the man who becomes Joker in Tim Burton’s Batman, played by Jack Nicholson.
But revealing so emphatically that the Joker is Jack Napier in this particular universe could be a forerunner to a similar origin story in the wider DC comics.
Murphy says his version of the character “is based more on TAS Napier, but there are Burton elements as well.”
He’s been given several origins over the years, some of them conflicting, and none of them fully revealing his past before his face was disfigured.