Who is the main assassin controlled by players in the first Assassin's Creed?

Altaïr Ibn-La'Ahad is the main assassin controlled by players in the first Assassin's Creed.

Altaïr is a Syrian member of the Assassin Brotherhood during the Third Crusade. At the beginning of the game, he loses his rank after a failed mission and must rebuild his reputation by carrying out assignments for the Brotherhood. His investigation leads him through cities including Masyaf, Jerusalem, Acre, and Damascus.

The character's name means “flying eagle, son of none” in Arabic. Altaïr is portrayed as highly skilled but initially arrogant, and the game's story follows his gradual development into a more thoughtful leader. His mentor is Al Mualim, the Brotherhood's master at Masyaf.

Altaïr is not the same character as Ezio Auditore, the Italian Renaissance assassin introduced in Assassin's Creed II. The games connect them through the series' ancestral-memory premise and through artifacts and writings that survive across centuries.