a senior member of the Assassin Brotherhood during the Third Crusade.
In 1191,Altaïr and two fellow Assassins-brothers Malik and Kadar Al-Sayf-are sent to Solomon's Temple to retrieve an artifact known as the Apple of Eden from the Brotherhood's sworn enemies,the Knights Templar. Blinded by arrogance,Altaïr botches the mission,resulting in Kadar's death;however,Malik is able to grab the Apple before escaping. Although Altaïr later partially redeems himself by fighting off a Templar attack on the Assassin home base of Masyaf,his mentor and superior,Al Mualim,demotes and orders him to assassinate 9 Targets in order to regain his previous position and honour.
After eliminating 8 Targets,Altaïr discovers all nine are Templars who had conspired to retrieve the Apple,revealed to be a relic of a long-forgotten civilization said to possess god-like powers. He also comes to question the nature of Al Mualim's orders while slowly becoming more humble and wise and make amends with Malik. During his assassinaction attempt on the last target,Robert de Sable,Altaïr is tricked with a decoy: a Templar named Maria Thorpe,who reveals that Robert had anticipated the Assassins would come after him and went to negotiate an alliance between the Crusaders and Saracens against them.
Sparing Maria's life,Altaïr confronts Robert in the camp of King Richard I and exposes his crimes. Unsure of whom to believe,Richard suggests a duel to determine the truth,remarking that God will decide the victor. Altaïr finally kills Robert,but not before he reveals that Al Mualim has betrayed both the Assassins and the Templars to acquire the Apple. He returns to Masyaf,where Al Mualim has used the Apple to enthrall the population,as part of his plan to end the Crusade and all conflict in the world by imposing order by force. With Malik and several Assassins help,Altaïr manage to resist the Apple's power and kills his Mentor. He unlocks the map,showing the locations of countless other pieces of Eden around the world.
In the present,the Assassins launch an unsuccessful attack on the Abstergo facility to rescue Desmond,resulting in most of them being killed. After completing Altaïr's memories,Vidic reveals to Desmond that Abstergo is a front for the modern-day Templars,seeking to find the remaining Pieces of Eden. With Desmond no longer useful,Vidic's superiors order him killed,but Lucy,who is implied to be an Assassin mole,convinces them to keep him alive for further testing. Desmond is left alone in his room,where he discovers strange drawings.