Peter is a nomadic vampire who roamed in North America with his mate Charlotte before joining the Coloradan Coven. He befriended Jasper Hale while they were in Maria's newborn coven and have been close as brothers ever since, therefore creating a loyalty with Jasper's mate, Alice Cullen.
Born in 1848, Peter was turned into a vampire at the age of 22 and was placed into Maria's newborn army. The army's second-in-command Jasper found a kindred spirit in Peter and was impressed with his combat abilities, and convinced Maria that Peter would be worth keeping. Jasper described him as a civilized vampire who didn't like to fight, even though he was good at it. With Jasper's help, Peter survived execution and lived through his first three years as a vampire. Peter knew Jasper had saved his life, and he felt indebted; he would do anything Jasper asked. He cheerfully took responsibility for the other newborns. He cared nothing about their fate, just like Jasper and Maria - until Maria brought Charlotte into the army.
Peter found out how Charlotte was different from the other newborns. Usually Maria selected humans she thought would make good warriors, but during her brief interludes of peaceful living, she was less picky. There were some women, a few physically older individuals, and some who were too young to be of much use. Charlotte was one of the vampires who did not have physical attributes or life experience that would lead to her being a good warrior. She was very small physically and scholarly by nature. She was the most self-controlled of all the fresh newborns, which gained Peter's attention. She was able to carry on a conversation, a rarity for newborns, and Peter found himself spending more and more time with her. At first Peter did not think he was in danger. Charlotte was interesting and oddly pleasant, but still just another newborn. She was also very pretty in a delicate way, but all the female recruits were beautiful. She was fun to talk to, but that was just killing time. It wasn't until nearly 9 months had passed that Peter suddenly realized she would be destroyed soon - and it wasn't until he imagined her gone that he realized how much she'd come to mean to him.
Peter waited for a good moment, and then spoke to Jasper about maybe preserving a few of the newborns. Jasper brushed him off, saying Maria would make that decision. In truth, Jasper had seen nothing special about any of the group. They were pooor soldiers; he wouldn't make any recommendations this time. Jasper could tell that Peter was agitated, but he assumed it was a similar emotion to his own depression. He thought Peter was opposed to the coming destruction in a general sense. Jasper knew Peter would need to get over that weakness in order to stay alive.
As the time for Charlotte's demise approached, Peter agonized over his options. To his understanding, the world was entirely made up of warring factions of strong vampires surrounded by newborns armies. He had powerful allies in Jasper and Maria; he was in as good a position as possible for a three-year-old vampire. His best option was to convince Jasper to leave Charlotte alive. Peter could barely conceive of trying to strike off on his own with Charlotte - they'd be massacred in no time.
Charlotte's time grew closer and Peter became more frantic. Again he tried to talk Jasper into letting him save the ones he wanted. He never said Charlotte's name, worried that drawing attention to her would prove dangerous for her. Jasper told him to relax and not worry about it - there was still plenty of time to make a decision. He promised to talk to Maria. Peter thought that sounded promising, so he waited. Jasper actually went to Maria to ask, for Peter's sake, but Maria felt that three permanent vampires were enough.
The night of the purge came a few weeks sooner than Peter had expected. As it began, he tried to control his panic. He begged Jasper to let him keep one or two. Jasper was adamant; Maria said all of them had to go. Peter tried frantically to come up with an answer as, one by one, he helped Jasper destroy the newborns. Then Jasper brought Charlotte out. She had no idea what was going on; she smiled when she saw Peter there.
Though he absolutely believed he and Charlotte would be slaughtered on their own, it was the only option he could think of. He didn't want to live if Charlotte was dead. He yelled for her to run, worried that she would be confused and hesitate. She didn't. He bolted after her, expecting to feel Jasper's teeth at any second, but there was no pursuit. They ran hundreds of miles before Peter paused to explain.
They moved up north and lived very cautiously in the beginning; it took them a while to figure out that not all vampires lived Maria's way. Over time, they grew very comfortable with their new world. Peter's only regret was leaving Jasper behind. He knew Jasper was his true friend because Jasper had not killed him for leaving. He also knew that Jasper was unhappy, and he was sure that, just like himself, Jasper had no idea of any other way of life.
Five years later, Peter decided to go back for Jasper. He told Charlotte he could move more inconscpicuously alone, but in fact he was trying to protect her. Peter knew Charlotte felt no loyalty or friendship for Jasper; she should not have to risk her life to try to help him. Peter would take the risk alone. He was shocked that Jasper was ready to leave after just one conversation. On the road, Jasper explained how things had changed with Maria. Peter was all for going back together and killing her, but Jasper was happy to not destroy her. Peter was surprised and couldn't miss the fact that Jasper wasn't much happier with him than he was with Maria. Peter tried to discover what was making Jasper so sad since he trouble controlling his thirst. Peter and Charlotte went on to discuss the trouble until Jasper recognized the source of his problems and left.
Peter missed Jasper, but couldn't help but enjoy how much happier he and Charlotte were without him. They pursued a comfortable nomadic existence, mostly in the Americas where they only hunt humans that were sinister and wicked towards the innocent. Peter kept tabs on his old friend and was thrilled when Jasper found Alice. Peter and Charlotte enjoyed to travel with them during the summer and went on steal blood bags which made Jasper happier. After Jasper and Alice joined the Cullen family, he and Charlotte stayed on good terms with all of them and visited them regularly.
Peter and Charlotte are mentioned by Jasper when he explains to Bella about his experiences with newborns and how it connects to the newborn army terrorizing Seattle.
When the Volturi threaten the Cullens' entire existence due to a mistaken report about the vampire hybrid Renesmee being an immortal child, Jasper suggests they find Peter and Charlotte to testify against their accusations.
Later, Alice and Jasper find Peter and Charlotte, and send them to Forks where their family explained the situation. Unlike the Denali Coven's initial reaction to Renesmee, they show less wariness, since they had never seen an immortal child before. After the situation was resolved in an almost completely peaceful way, Peter and Charlotte share a conversation with Jasper before departing.
Peter is described as being as tall as Jasper. As a human-feeding vampire, he has red eyes. He wears jeans upheld by a cowboy-belt and a gray vest, a blue shirt along with a brown leather jacket.
Peter is not known for his restraint, as he was raised by Maria, who just wanted her troops strong. Peter's emotions shine through quite clearly about the way he feels for Charlotte. He has a strong sense of loyalty to Jasper and thinks of him as a brother of sorts. Jasper likes Peter partially for his combat skills, and his kindred spirit. During his life as a vampire, he and Charlotte only hunted humans that were sinister. However, they went on to steal blood bags instead.