In the first Assassin's Creed game, what is the name of the playable Assassin set in the Third Crusade?

The playable Assassin in the first Assassin's Creed game is Altaïr Ibn-La'Ahad.

Released in 2007, the game follows Altaïr during the Third Crusade, mainly in the cities of Jerusalem, Acre, and Damascus. He begins as a highly ranked Assassin but loses his status after a failed mission, then must complete a series of investigations and assassinations to regain his position.

Altaïr's name is sometimes written with different transliteration and punctuation, including Altaïr Ibn-La'Ahad and Altaïr Ibn La-Ahad. The character is distinct from Ezio Auditore, the Italian Assassin who leads Assassin's Creed II, Brotherhood, and Revelations. Altaïr also appears in later games and stories, especially Assassin's Creed: Revelations, which explores his later life and legacy.

The first game introduced the series' central conflict between the Assassins and Templars, as well as the Animus framing device that connects historical characters to the modern era.