Oh boy. Katar's not the nicest girl at the princess academy, and she and Miri don't exactly get along—after all, they're both vying for the coveted position of academy princess, and Katar makes it no secret that she wants to claw the title away from Miri. She also has no shame about talking smack in front of Miri:
Miri started on her way again, and the girls quieted as she passed. Liana smiled uncomfortably, Bena glared at the ground, but Katar stared at Miri, her expression unrepentant. (5.31)
But despite all her nastiness, it turns out that Katar is harboring some pain and insecurities underneath her tough exterior. When Miri comes up to her after she's been named academy princess, Katar cries and reveals that she just wanted to get away from Mount Eskel because no one loves her here:
"My father doesn't look at me at all," said Katar. "Maybe he blames me for my mother dying when I was born, or maybe he just wishes I were a boy or some other girl entirely. Everything about this place is cold and hard and sharp and mean and… and I just want to go away. I want to be somebody else and see other things. And now I never will." (16.89)
Katar's prickly personality might be actually be a front to keep her from getting hurt; at home her father doesn't really pay attention to her, and the other girls don't consider her a real friend. When Miri sees how vulnerable and sad Katar is, she understands her better and encourages Britta to choose Katar as Mount Eskel's delegate. The girl just needs to get out of the village and start afresh.