Pip was an English student in the boys' 4th grade class. He was widely disliked and bullied often for his accent and foreign mannerisms. Despite being the butt-end of bullying at the school, Pip maintained his cheery and optimistic attitude.
The only exception to Pip's consistent happiness is when he's called "French," which was shown in the episode "Conjoined Fetus Lady" to anger him and cause him to throw a dodge ball at whoever insulted him.
In "Conjoined Fetus Lady," he tells Stan that he was an "archery esquire at Stratfordshire," before proving that he is indeed skilled in archery.
He had auditioned to be the boys' new fourth friend after Kenny died, but was told to "get the fudge out!" after asking for crumpets at a baseball game with Stan, Kyle and Cartman.
In the episode "Summer Sucks," Pip told the main four that his parents were dead. However, in "Two Guys Naked in a Hot Tub," he was put into the kids' room, implying that he perhaps has an adoptive home or is living with a relative. In the episode "Pip," it is shown that he lived with his abusive sister and her husband in England.
He died in the episode "201" after asking Mecha-Streisand to stop destroying South Park, which ended with Mecha-Streisand crushing Pip with her foot. Pip has not made a reappearance since.
You are an outcast, often belittled and abused by your peers. People with Pip Pirrup DNA are friendly, if socially awkward, but are nevertheless targeted by the universe for reasons outside their understanding.
"Hello, my name is Philip, but everyone calls me Pip, because they hate me."