Antagonist

"'Oh, Kathy, how are you? If you don't mind, we've got something to discuss just now. We'll be finished in just a minuete. Sorry.'" (54)

From when Kathy first introduced Ruth, she seemed dominant. She was always the center of attention, the most popular of their group. This is the first time that Ruth punishes Kathy for something that should have been discussed, then forgotten. And, even further Ruth's punishment came after her own mistake. She was the one that cheated, but she punished  Kathy for reacting, because she was used to getting her way. She always commanded the attention, and for that people probably ceded to her requests. So, Ruth was not used to people standing up to her, and when Kathy did, she decided to teach Kathy to follow in step. This worked in the end, because when confronted by another student that fell under Ruth's wrath, she decided to stick up for Ruth and decided that she wanted back in the group. This pattern continues throughout the story with Kathy being submissive until she can't take it any longer and confronts Ruth, only to feel like it was her fault in the end.