Kaisa appears to be a young female adult witch who is known for being the keeper of the books at the Trolberg library. Kaisa is usually calm, but can be rather strict with rules. She has the uncanny ability to always know exactly what book people are looking for, even before they can ask her about it. She sometimes also has some feelings of insecurity about her abilities as a witch, believing she wasn't the witch she was trained to be, and to think she would dissapoint her teacher, Matilda Pilqvist (a.k.a Tildy). But with some help from Hilda, she along with Tildy proves that Kaisa never let Tildy down and she's happy to be her former mentor. Kaisa seems like a very calm and kind person who is content with most things, even if it means offering someone information, advice, or a task to handle and has a little sense of humor.