J.K. Rowling created Newt Scamander as the fictional author of Fantastic Beasts and Where to Find Them.
Newt Scamander is presented as the author of a Hogwarts textbook titled Fantastic Beasts and Where to Find Them. Rowling published a real charity edition of the textbook in 2001, with proceeds benefiting Comic Relief. The book is framed as Harry Potter’s school text and includes humorous annotations attributed to Harry and Ron.
Rowling later wrote the screenplay for the 2016 film Fantastic Beasts and Where to Find Them, which turned Newt into the central on-screen character. Eddie Redmayne played him in the film series. The films expand his background as a magizoologist and move the story beyond Hogwarts.
Newt is therefore both a fictional author within the wizarding world and a protagonist in a separate film series. He is not the same character as Hagrid, who teaches Care of Magical Creatures at Hogwarts.