Hyacinthe appears in every book but Kushiel's Chosen and Kushiel's Scion.
Anasztaizia, Hyacinthe's mother, was abandoned by her family after she had lost her virture by being raped by a D'Angeline. She earned her money in part by using the dromonde to tell fortunes.
In Kushiel's DartEdit
Hyacinthe and Phedre met when Phedre escaped from Cereus House the day she was to meet Delaunay. They quickly became best friends and worked together to try to solve the mystery of Delaunay's past, though Anasztaizia warned that Phedre would regret the day she learned solved the puzzle.
Hyacinthe accompanied Phedre and Joscelin on their journey to Alba to assist Drustan in winning his crown. It was his idea that Joscelin dress as a Mendacant and that they follow Tsingani routes. On their way, they come across a Tsingani horse fair, and Hyacinthe for the first time meets his mother's family, who accept him eagerly. However, he too is cast out when he speaks the dromonde to ease Phedre's fears when she spots Melisande at the fair.
When they arrive in Alba, Hyacinthe feels an affinity for Drustan's sisters, as they also have the gift of prophecy. He begins to have feelings for Drustan's youngest sister, Moiread. Unfortunately, Moiread is killed during the battle for Bryn Gorrydum. The death of Moiread hits Hyacinthe hard, and Phedre tries to comfort him by using her skills as a servant of Naamah.
On their way back to Terre d'Ange, they are stopped by the Master of the Straits, who calls Hyacinthe and others ashore to the Three Sisters. The Master of the Straits bids his captives solve a riddle before they may leave, the catch being that the one who solves the riddle is doomed to become the new Master of the Straits--control the waters between Alba and Terre d'Ange, and to age but live eternally. Though Phedre solves the riddle first, Hyacinthe sacrifices himself by using the dromonde to look backwards into history and give a more complete answer. He then enters training to become the next Master of the Straits upon the death of the current Master--the son of Rahab. Before she leaves, Phedre again uses Naamah's arts to comfort Hyacinthe.
In Kushiel's AvatarEdit
The son of Rahab dies and Hyacinthe takes over as Master of the Straits. Meanwhile, Phedre has been searching for the means to free Hyacinthe from his curse. After a long wait for Hyacinthe, she speaks the name of the One God and binds Rahab, freeing him. Afterwards, although the Tsingani want him to be their leader, Hyacinthe declines, and instead chooses to marry Sibeal and live in Alba.
In Kushiel's JusticeEdit
Hyacinthe and Drustan's sister Sibeal are married and have children, yet they refuse to allow their children to become the next Cruarch of the mother of the next Cruarch, though this would solve the problem of those in Terre d'Ange who wish to ensure D'Angeline influence in Alba for years to come. Hyacinthe asks Phedre and Joscelin to hide the pages of the lost book of Raziel that taught Hyacinthe his power.
In Kushiel's MercyEdit
At Imriel's request, Hyacinthe searches for Melisande in his sea mirror over Alba and Terre d'Ange to no avail.
After Carthage has been defeated, Hyacinthe threatens that if Carthage ever hurts those he loves again, he will not hesitate to sink it beneath the waves, which suggest he, as the Master of the Straits, has power over more water than just the body of water called the staits between Alba and Terre D'Ange.