"Wise beyond her years and suspicious of Jim's strange behavior, Claire finally gets her answers when she discovers her baby brother was swapped for a Changeling Troll! She is then introduced to a wondrous world full of Trolls and magic. However, this doesn't distract her from her quest to save her brother no matter the odds or obstacles, though it helps that Jim is willing to do almost anything for her. She becomes an integral part of the Trollhunting team with her sharp wit and strong loyalty to friends and family. Far from the damsel in distress, Claire fights for herself and learns to master a weapon of her own: the Shadow Staff."
Claire is a slim girl with dark brown eyes and black hair with blue and purple streaks in it. She wears a light purple turtleneck shirt with a darker pink skull and the words hamlet under a short dark blue jacket, a short blue skirt and blue leggings with black shoes.
- “You mean WE are gonna find him... together.”
- ―Claire to Jim in "The Battle of Two Bridges"
At first, Jim merely crushed on her from afar, until he attempted to woo her with quickly learned Spanish and she invited him to audition for the school play, Romeo and Juliet. Although he doesn't actually want to act, he auditions to get closer to Claire. However, due to his tardiness and absence from several rehearsals, their relationship begins to turn sour. After a last minute attempt to win back her trust, he agrees to babysit her little brother, Enrique, who is actually NotEnrique. After causing a mess in her house, she says she never wants to talk to him again. Before he and Draal have their to-the-death rematch, he leaves her a letter, confessing all of his feelings and what has been going on with him. She forgives him, thinking it's metaphorical, but then grows suspicious and, after NotEnrique endangers her and she learns the truth, the two grow closer as she joins in on the adventures, and prepare to go to the Spring Fling together. They ultimately decide to skip the Fling, and instead dance near a cliff overlooking the city, almost kissing.
NotEnrique and Claire share a rocky relationship. Although shown to argue, they are rather close and he even showed Claire that her real brother is safe. They act much like real brothers and sisters. As the series progresses this bond is shown to grow stronger to the point when he begins referring to Claire as Sis, and should she be harmed he makes statements such as Keep your hands off my sister!.
- In the book series, Claire has longer hair and was Scottish.
- Her favorite food is guacamole and would bathe in it.
- She becomes the first human, and apparently the first female to wield Angor Rot's former weapon, the Shadow Staff.
- Her surname in the book was Fontaine.