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 him 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.
The name Petronelle shares an identical ending with the name Edelle, which is curious as both of the people bearing these names are Fellan or at least partially in Petronelle's case. It might also be a common Dorneish name or common name in the world's common language in general, which is English to the audience, since the -elle ending is used in real world English to form feminine proper names.
The name Petronelle might be derived from the name Petronella or Pentronilla, which is a Late Latin feminine given name and the diminutive from of Petronia, itself the feminine form of Petronius, a Roman family name. Saint Petronilla is the name of an early Roman saint who were later interpreted to be the daughter of Saint Peter, the apostle and disciple of Jesus Christ. Saint Petronilla became the saint of the Frankish kings, and her chapel became the burial place for French kings. The derived form of Petronella, which was later changed to Pieternella, has been popular in the Netherlands since the Middle Ages, possily due to Gertrude, Countess of Holland, adopting this name around 1100. In daily life, many people with this name is given a short nickname form, such as Petra, Nel, Nelleke, Nelly, Ella, Ellen and Elly.