Kathleen is a shy and silent girl. She was living with her aunt because her father's living abroad, so her time at St. Clare wasn't pleasant at all. Her aunt was really stingy and only gave Kathleen 1 penny a week. Because Kathleen didn't want to admit that she was poor, everyone thought that she was mean and a cheapskate. She started stealing other girls' pocket money and bought them various stuff, only to get caught after few times. Even though she was suspicious of stealing, Isabel never doubted her, and couldn't believe that she was thinking bad about Kathleen.

But in the inside, Kathleen's a really good girl and she was great help to the twins when they moved there. She's also good ad sports, lacrosse specifically. Belinda even choose Kathleen to play in a match for the school.