In Assassin's Creed, Altaïr Ibn-La'Ahad's mentor and leader of the Levantine Assassins is Al Mualim.
Al Mualim, whose name means “the Teacher” in Arabic, leads the Assassin bureau in Masyaf during the events of the first game. He assigns Altaïr a series of assassination missions across the Holy Land in 1191, during the Third Crusade.
The character is important because he initially appears to be the ultimate authority in Altaïr's world. After Altaïr kills the nine targets assigned to him, however, the game reveals that Al Mualim has been pursuing the Apple of Eden for his own purposes. This makes him both Altaïr's teacher and the game's final major adversary.
Players sometimes confuse Al Mualim with Rashid ad-Din Sinan, the historical leader of the real Nizari Ismaili state, on whom the character is loosely based. The game's fictional story uses historical settings and names but is not a documentary account.