Mary Sue characters are found in much beginning fiction, especially fan fiction. They are to be avoided at all costs. But what is a Mary Sue character, and why are they bad?
Beginning fiction writers often have trouble creating believable characters. Some seem to create fiction as an extension, or escape, from their own boring life.
A Mary Sue character is injected into a story so that the writer may live vicariously through them. They are usually perfect, beautiful, and directly responsible for the story’s happy ending. Mary Sue characters get the most handsome male character, are friends with all the rest, and never messes up.