Peter is a nomadic vampire roaming North America with his mate Charlotte. Neither are vegetarian.
In the partial draft of Midnight Sun, Peter is described as being almost as tall as Jasper, with long, white blond hair. As a human-feeding vampire, he would also have red eyes.
Peter was originally created during the Southern Wars as part of Maria's army. Against long odds, he survived his first three years. His job was to care for the newborns, full-time. He was later befriended by Jasper, and fell in love with the newborn Charlotte. Jasper described him as a civilized vampire who didn't like to fight, even though he was good at it.
One day Jasper was ordered by Maria to kill all the 'pawns'; newborns past their first year. Jasper requested Peter's help. Peter tried to persuade Jasper that some had potential, but Jasper disagreed. After a long night of killing, Jasper could see it was taking a toll on Peter. When Jasper called out the next name on the list, Peter was suddenly furious. When Charlotte appeared, Peter changed; his feelings gave him away. He shouted for her to run, bolting after her. Both escaped successfully.
Five years later, Peter returned for Jasper, who had also left. By this time, Peter and Charlotte were now mated. While traveling with Jasper, Peter noticed his depression was always worse after they hunted. Jasper left after a few years traveling with the couple, since he couldn't handle the overwhelming emotions of his prey. Peter and Charlotte didn't feel the same way; they only wanted release from fighting. After Jasper settled with the Cullens, Peter and Charlotte visited regularly. In Midnight Sun, Alice sees Peter and Charlotte coming to visit and Edward has issues concerning Bella, mentioning that Peter isn't known for his self-control.
Peter later visited Forks with Charlotte, and served as witness against the Volturi. Jasper said their names in Breaking Dawn almost halfheartedly, as if he didn't want to lose his friend. They came anyway, and weren't as wary of Renesmee as the Denali clan, since they had never seen an immortal child before. When it was over, they were among the last to leave.
From the Greek "Petros" meaning "stone."