Garwin Chang is a human boy that was in Sophie's high school senior class. He is only in one scene in the entire series, an early scene in the first book, Keeper of the Lost Cities. In this book, he is wearing a T-shirt that said "BACK OFF! I'M GONNA FART!".
He was one of the many kids that teased Sophie, though he teased many more people than just Sophie. After she answered a question from Mr. Sweeney, the teacher, he said to her, "Nice job, Superfreak." He was bitter that he had been rejected by Yale, while Sophie, who is much younger than him (around 5 or 6 years younger), had received a full scholarship.