Harry was told there were four Marauders. That was a lie. Harry was told there were three unregistered animagi. That was a lie. In fact there was another. One that was never told. No one knows why, but maybe that’s because to Sirius, it was too much of a painful story to reveal. Maybe something had happened to the Secret Marauder, but whatever it was, Sirius lied, and he lied because of love. http://maddening-the-unhelpful.tumblr.com/post/87288455705/because-if-people-were-books-she-was-a-library