Katie is most notable for being Sadie's best friend. They do everything together, even wear the same outfits (which Katie sews herself). Like Sadie, Katie is a sensitive, cheerful, and sweet-natured girl. She is boy-crazy and when she has grown attracted to someone, she (and Sadie) will fawn over him endlessly. Katie can be considered the more passionate one between her and her best friend. Her biography states that she "thinks with her heart," in contract to Sadie, who "thinks with her head." She is shown to have a bad sense of direction, a flaw which produces tragic results. Sadie's label of The Sweet Girl's Friend may imply that Katie is more independent and capable of making decisions on her own. However, given her thinking habits, they don't always turn out to be wise.