Ghislaine looks young and beautiful with curly black hair, brown skin, and sea-green eyes.
Most notable among Ghislaine's personality traits is her razor-sharp intelligence. She enjoys reading and researching, and she often serves as a source of information for Manon. If interrupted while reading, she tends to become irritated and snarky. On the battlefield, however, she fights expertly and obediently. Her battle prowess and her brains combined make her a formidable member of the Thirteen.
Her twelve years at mortal school caused her to pick up and cling onto some human behaviors and gestures.
It had been an expectation when Ghislaine's mother had convinced the High Witch to send her daughter to a mortal school in Terrasen a hundred years ago. She had learned magic and book-things and whatever else mortals were taught and while the witch had returned twelve years later, the witch had been...different. Still a Blackbeak, still bloodthirsty, but somehow more human.
Ghislaine is introduced in Heir of Fire as one of Manon’s Thirteen.
Upon discovering a connection between the Valg and the Ironteeth witches, Manon Blackbeak decides to investigate further. She comes to Ghislaine, whose twelve years in a mortal school has given her a rare love of reading and information retention. Manon interrupts Ghislaine as she is reading in her room and the other witch is irritable, a trait Manon lets slide because Ghislaine is the perfect soldier on a battlefield and Manon respects her right to have a different attitude while in her own space. Manon questions Ghislaine’s knowledge about the Valg and Ghislaine begins to explain the longtime connection between the witches and the Valg. Upon seeing Manon’s eyes glaze over with boredom, Ghislaine summarized the information. She tells Manon that the witches are products of the Fae and the Valg, the Ironteeth witches taking more after their demonic ancestors while the Crochans take after the Fae. When Manon asks if the Valg are potential allies, Ghislaine shows surprising dismay at the idea, stating that the Valg are truer monsters than even the Ironteeth.
Ghislaine takes part in the siege on Rifthold. She is present at Manon’s trial and Asterin’s subsequent execution where she and the rest of the Thirteen help Asterin escape. Ghislaine is with the Thirteen when they attack Maeve’s fleet and she is expected to go with Manon and Dorian Havilliard to find the Crochan witches in Kingdom of Ashes.