Anja was born to a fisherman of the Moonshae Isles and his wife, Katja, a lycanthrope. One full moon, Katja broke free of the shackles she used to protect her family from herself. Anja's father died shortly after locking Anja in a pantry, mauled to death by the transformed Katja. Fearing for Anja's safety and the possibility of Anja being a lycanthrope herself, Katja fled across the Sea of Swords to the Misty Forest, seeking the aid of three witches rumored to live there. The witches agreed to raise Anja and help her control her lycanthropy in exchange for Katja's right index finger, a valuable component for magical rituals. Katja reluctantly agreed, leaving behind only her severed finger and a beaded necklace adorned with bear claws. Anja's only memory of her mother is her trailing red hair and the sounds of sobbing.
The three witches (Bruna, Meyorre, and Ydole) raised Anja in the Misty Forest and taught her the ways of witchcraft over many years. Through monthly rituals they were able to prevent Anja from changing during a full moon. While not maternal by nature, the three witches showed Anja affection in their own unique ways and encouraged Anja to become a strong, independent woman. The older she grew, the farther and more frequently she ventured from her home in the Misty Forest, always returning in time for the lunar ritual. Upon adulthood, she established a cramped medicinal shop in Waterdeep, providing herbs and treatment to the overflowing population.