Anasztaizia, Hyacinthe's mother, was abandoned by her family after they believed she lost her virtue by being raped by a D'Angeline. She earned her money in part by using the dromonde to tell fortunes.
In Kushiel's Dart
Hyacinthe met Phèdre nó Delaunay de Montrève when Phèdre escaped from Cereus House the day she was to meet Anafiel Delaunay. They quickly became best friends and worked together to try to solve the mystery of Delaunay's past, though Anasztaizia warned that Phèdre would rue the day she learned solved the puzzle.
During the Bitterest Winter, Hyacinthe's mother died from the plague that swept through the City of Elua. Hyacinthe took over her business and was sad that she never got to see him
When Phèdre returned to Terre d'Ange after being captive in Skaldia, she turned to Hyacinthe as one of the few people she could trust. Hyacinthe helped Phedre and Joscelin contact Thelesis de Mornay, who obtained for them an audience with Ysandre de la Courcel.
Hyacinthe accompanied Phèdre and Joscelin Verreuil on their journey to Alba to assist Drustan mab Necthana in winning his crown. To disguise themselves from Melisande, Hyacinthe suggested Phedre dress as a Tsingani woman and Joscelin a Mendacant, and that they follow Tsingani routes. On their way to Rousse's fleet, they encountered a Tsingani horse fair, where Hyacinthe for the first time met his mother's family, who accept him eagerly. However, he was cast out when speaking the dromonde to ease Phèdre's fears when she spotted Melisande Shahrizai days later.
When they arrive in Alba, Hyacinthe felt an affinity for Drustan's sisters, as they also had the gift of prophecy. He began to have feelings for Drustan's youngest sister, Moiread mab Necthana, which she appeared to reciprocate. However, Moiread was killed during the Battle of Bryn Gorrydum, preventing them from exploring their budding relationship further. The death of Moiread hit Hyacinthe hard. Phèdre comforted him using her skills as a servant of Naamah.
On their way back to Terre d'Ange, they were trapped by the Master of the Straits, who called Hyacinthe and others ashore to the Three Sisters. The Master of the Straits bid 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 Phèdre solved the riddle first, Hyacinthe sacrificed himself by using the dromonde to look backwards into history and give a more complete answer. He then entered training to become the next Master of the Straits upon the death of the current Master—the son of Rahab. Before she left, Phèdre again used Naamah's arts to comfort Hyacinthe. Years later, he told Phedre that it was the only that kept him going through his long ordeal.
In Kushiel's Avatar
Over ten years after Hyacinthe's apprenticeship began, the son of Rahab died and Hyacinthe took over as Master of the Straits. Meanwhile, Phèdre had been searching for the means to free Hyacinthe from his curse, and went on a long quest to find the Name of God, the only thing that could make Rahab undo his geis. After a long wait for Hyacinthe, she spoke the name of the One God and bound Rahab, freeing Hyacinthe. Afterwards, although the Tsingani wanted him to be their leader, Hyacinthe declined, instead choosing to marry Sibeal and settle in Alba.
In Kushiel's Justice
Hyacinthe and Drustan's sister Sibeal mab Necthana married and had two children. They refused to allow their children to become the next Cruarch or the mother of the next Cruarch, though this would have solved the problem of those in Terre d'Ange who wished to ensure D'Angeline influence in Alba for years to come.
During Imriel, Dorelei and their entourage's stay in the Stormkeep, Hyacinthe asked Phèdre and Joscelin to scatter and hide the pages of the lost book of Raziel that taught Hyacinthe his power.
In Kushiel's Mercy
At Imriel nó Montrève de la Courcel's request, Hyacinthe searches for Melisande in his sea mirror over Alba and Terre d'Ange to no avail.
After Carthage was defeated, Hyacinthe threatened that if Carthage ever hurts those he loves again, he would not hesitate to sink it beneath the waves, suggesting he, as the Master of the Straits, has power over more water than just the body of water called the Straits between Alba and Terre D'Ange.