Who is the main character in the book, Fantastic Beasts and Where to Find Them?

Newt Scamander, the fictional author of this book, can perhaps be considered the book's primary "character" because it is his knowledge of "magizoology" that qualified him to write the bestiary and it is Rowling's knowledge of him that allows him to do it. Scamander, of course, is simply a pen name for J. K. Rowling, but his character existed in her mind and in her other books long before this book was published.