What is the complete name of Assassin's Creed's first protagonist, Altaïr?

The complete name of Assassin's Creed's first protagonist is Altaïr Ibn-La'Ahad.

Altaïr Ibn-La'Ahad is the central character of the original Assassin's Creed. He is an Assassin operating in the Levant during the Third Crusade, with missions taking place in cities including Masyaf, Jerusalem, Acre, and Damascus. His actions are framed through Desmond Miles's experiences with the Animus in the modern-day storyline.

Altaïr begins the game as a highly skilled but overconfident Assassin. After a failed mission, he is demoted and must complete a series of investigations before regaining his status. His relationship with Al Mualim, the Mentor of the Assassin order, becomes crucial to the story's revelations about loyalty, power, and the Apple of Eden.

Ezio Auditore, Ratonhnhaké:ton, and Arno Dorian are protagonists of later games. Altaïr's full name is often shortened in casual discussion, but Ibn-La'Ahad is part of his canonical name.