Petronelle is the half-Fellan nurse of Lady Janna and Zak. Due to her Fellan blood, she is constantly distrusted among Farr and his councillors, who believe that the Fellan are evil and the enemies of humans. However, she has a constant supporter in Lady Janna, who trusts her with her life.
Petronelle was chosen as a nurse for Janna by Janna's parents, who were of the Deltoran city of D'Or. It is unknown exactly when Petronelle was selected, but it is clear that she settled in Dorne when Lady Janna was wed to Chieftain Farr, and became nurse to their son Zak. As tensions between Fellan and humans increased, Petronelle was viewed with suspicion due to her Fellan blood, though Janna was a strong supporter of her and trusted her with her son's life and her own. When Rye of Weld was injured protecting Zak, Petronelle nursed his back to health and named him Keelin, as she did not know his real name. It was soon clear that he had amnesia, though Petronelle assured him and later Chieftain Farr that it was only temporary.
While bathing Keelin she discovered that he was a copper-head, and encouraged him to keep his hair hidden from view, as red hair is the sign of a Fellan and disliked by the people. Petronelle suspected that Keelin was special, and that she was born to meet and help him. She found a small pouch of strange items on his personage, and kept it safely hidden for him, suspecting that they were important. In trying to keep Keelin safe, she lied to Farr and Janna, and did not tell them everything she had discovered about him. This caused her remorse, as she valued the trust they had in her, and she prayed that she was right in doing so. Eventually she made Keelin promise never to harm Farr, Janna or Zak, and help Farr in his struggle and be loyal to Farr to the death.
When Janna was found to be poisoned, Petronelle nursed her back to health, and later went with her onto the riverboat to try and stop Farr's assault on the Fellan.