Ladies and Gentlemen, may we introduce the Evil Queen of Mica High: Hillari Kimble.
Okay, maybe we're being a bit harsh, but really, Hillari is just plain not nice. It is only moments after Stargirl's arrival at school when Hillari starts being mean. She wastes no time in telling everyone that "she's not real" (2.7). To Hillari, Stargirl is just too confident to actually be genuine. The idea that such a girl could be comfortable in her own skin makes no sense to Miss Kimble.
We never learn the motivating factor behind Hillari's nastiness to Stargirl, because we don't know much about her at all. All we know, in fact, is that she hates Stargirl. Shmoop, though, is never afraid to hazard a few guesses: Maybe Hillari is insecure in her position in the school and sees Stargirl as some kind of threat. Maybe it's because everyone pays attention to Stargirl now, instead of Hillari. Or maybe she's just nasty, plain and simple.
Often, that last theory seems to be the most convincing. Hillari is an all-around jerk to Stargirl, and she never changes course. Let's take a look at some of her meanest deeds:
There is an upside to Hillari's put-downs. In many ways, Hillari is there to emphasize Stargirl's kindness. Even though Stargirl is so ridiculously mean, Stargirl is relentlessly kind to her tormentor. This is really clear after the slap at the dance. In response to the slap, Stargirl gently kisses Hillari on the cheek. In Shmoop's book, that's a point in Stargirl's column, because she simply refuses to stoop to Hillari's level.