|“|| You want to know the grand Crochan secret? Our great truth that we keep from you, that we guard with our lives? It is not where we hide, or how to break your curse. You have known all this time how to break it—you have known for five hundred years that your salvation lies in your hands alone. No, our great secret is that we pity you.
–Rhiannon - Heir of Fire
Rhiannon was described as a brown haired witch with eyes the colour of freshly tilled earth.
|“|| Look all you want. Look at what they did to me, your sisters. How it must pain them to know they couldn't break me in the end.
–Rhiannon - Heir of Fire
Rhiannon was very devoted to her family, carrying on the search for Manon even after her father's death.
She diplays great courage and perception, not showing any fear at her impending execution and realising that her death was meant to be a challenge instead of a gift. She points out that the Ironteeth were unable to break her.
Rhiannon is captured by Iskra Yellowlegs after being caught spying on the Ironteeth. She is brutally interrogated for two days afterwards before being brought before Manon to be killed. The Blackbeak Matron is present at the execution.
Rhiannon is forced to kneel before Manon, battered and bloody, and tells Manon that she knows her; she is on top of the Crochans' kill-on-sight list, and is referred to as the White Demon. She goes on to reveal that she knows the true purpose for her execution, and points out her wounds to Manon, challenging her to look at them. Coughing up blood through broken teeth and cracked lips, Rhiannon says that the Crochans pity the Ironteeth for being made monsters by the Matron's brutal treatment, and tells Manon that she was made a monster, and not born one. The Matron interrupts, and Rhiannon quietly begs Manon to kill her. Manon cuts her throat, and takes her red cloak afterwards.
When Manon attacks the Blackbeak Matron rather than kill Asterin Blackbeak, the Matron cruelly informs her that the witch she killed was her own half-sister, caught looking for her after so many years. She tells Manon the witch's name, Rhiannon, and mocks Manon for being a Crochan Queen.
Manon is bothered by this revelation throughout the rest of the book.
|“|| "You know what we call you?" Blood welled as the Crochan's lips peeled into a smile. She closed her eyes as if savoring it. "We call you the White Demon. You're on our list—the list of all you monsters to kill on sight if we ever run into you. And you..." She opened her eyes and grinned, defiant, furious. "You are at the top of that list. For all that you have done."
–Rhiannon to Manon - Heir of Fire
- The Blackbeak Matron mentions in Empire of Storms that Rhiannon told her of her kinship with Manon, thinking it would save her.
- She also says that Rhiannon decided not to reveal her identity after seeing what Manon had become.