He was portrayed by Samuel Le Bihan.
The handsome and libertine French naturalist Grégoire de Fronsac was in new France in the Americas to study native fauna, but got caught up in the fighting with the English. While with the troops of ruthless French general, he witnessed the officer order the slaughter of a friendly Haudenosaunee (Iroquois) Mohawk tribe, with only one survivor kept alive to act as a guide. A few weeks later Grégoire discovered the guide, Mani, slitting the general's throat. Rather than raise the alarm, the two left together and over the following months kept one another laive, eventually becoming blood brothers. When Grégoire returned to France, Mani accompanied him. A few years later, during the mid-1760s Grégoire, by now a knight and the royal taxidermist, was sent by King Louis XV of France to Gévaudan, with orders to study the Beast terrosing the region, and to stuff its corpse once the army caught it. While there Grégoire falls in love with beautiful noblewoman Marianne de Morangias. He later discovers that her brother, Jean-François de Morangias, the main antagonist's movie was the Beast's master and a member of a secret society, the Wolves of God, headed by local priest Henri Sardis, which was using fear of the Beast as a weapon against the King's perceived unholy (liberal or enlightned) ways.
The Beast evaded the army's efforts, and it fell to Mani and Grégoire to hunt the creature. After driving it intop a trap, the pair and their ally, the young Marquis Thomas d'Apcher severly wounded the Beast, which fled. While Grégoire saw to the wounded Marquis, Mani pursued the Beast, only to be murdered by Jean-François. Identifying Mani's killer by his distinctive silver shot, Grégoire avenged his friend's death, breaking the society with the assistance of the Pope's secret, the mysterious and alluring Sylvia and killing Jean-François in a single combat. Afterwards Grégoire and Marianne apparently departed to Africa together.