Paul Peterson is Mr. Peabody and Sherman's arch-friend. He was rumored to be one of the main villains, however the release of the film in the U.K. revealed this to be a hoax, the real villains are Mrs. Grunion and Ay.
However, he stil serves as the tertiary antagonist and antihero of the film.
He starts off being grumpy and missunderstanding Peabody's good intentions, thinking it's his fault because of Mrs. Grunion. However, when he had the abillity to dance and stop his back pains, he turned good until he saw Peabody biting Mrs. Grunion. Then he turned good again near the end of the film after Sherman's speech.
To be added.
He is the only one in Peterson family whose name do not end with "y".