Katerina, often called Kat for short, is Antimony's best friend. They first met around Antimony's first year at the court when Kat introduced herself to her. She is also the one who gave her the nickname "Annie". The two girls weren't friends immediately, but just a couple of kids that hung out occasionally, and it was only when Annie opened up under the cherry tree in the Decontamination Habitat that their friendship was set in stone. Since then, they have gone on a multitde of adventures together.