Arno Dorian is the Parisian assassin who investigates the murder of his adoptive father in Assassin's Creed Unity.
Arno is the game's central character, and his story unfolds during the French Revolution. His adoptive father, François de la Serre, is a Templar grand master who is murdered early in the narrative. Arno is blamed for the crime and later joins the Assassin Brotherhood while trying to discover who arranged the killing.
The investigation brings Arno into conflict and cooperation with members of both secret orders. Élise de la Serre, François's biological daughter and Arno's childhood companion, is a major character whose Templar background complicates their relationship.
Unity is notable for its detailed recreation of Paris and for introducing cooperative missions that can be played with other human players. Napoleon Bonaparte appears in the story, but he is a historical figure rather than the protagonist. Pierre Bellec is an Assassin mentor, while Élise is Arno's ally and rival in the investigation.