Great characters in fiction

In popular fiction there are a handful of characters who have exceeded their creators in fame and popularity. Two such who easily come to mind are Sherlock Holmes created by Sir Arthur Conan Doyle and Harry Potter by J K Rowling. Sherlock Holmes, the original cerebral detective was created by Sir Arthur CD in 17th century, in an age where there was no visual media, yet he became the benchmark for all later authors of crime fiction. His deductions were so startling and surprising and his mannerisms and physical appearance and gestures so 'singular' that they became iconic. Harry Potter, the beloved boy wizard is so popular that almost every other child knows about him and his adventures. In the visual age, his character has been bought to life on screen very suitably by Daniel Radcliffe. Few characters are there in child fiction who are as popular as Harry. In Enid Blyton's books of course we had characters we all identified with and were interested in like George in Famous Five books or Fatty in the Five find outers and dog. But these books revolved more around the mystery or adventure the characters get into rather than the central character. What makes these characters stand out more than any other. One must be the sheer originality of the character sketch. Sherlock Holmes was THE detective on which Agatha Christie sketched Hercule Poirot's quirks and Miss Marple's character.