In the first Assassin’s Creed game, Altaïr’s mentor and Masyaf leader is Al Mualim.
Al Mualim, whose name means “the teacher” in Arabic, leads the Assassin Brotherhood from its stronghold at Masyaf during the game’s 12th-century storyline. After Altaïr breaks the Brotherhood’s three core tenets during a mission at Solomon’s Temple, Al Mualim demotes him and assigns a series of assassination targets as a path to redemption.
The targets are connected to political conflicts in the Holy Land, including the Third Crusade. Al Mualim presents the missions as a way for Altaïr to uncover a larger conspiracy, but his own motives become increasingly suspicious as the story progresses.
A common mix-up is confusing Al Mualim with Rashid ad-Din Sinan, the historical leader associated with the medieval Nizari Ismaili community. Assassin’s Creed fictionalizes and dramatizes that historical background, while Al Mualim is the game’s in-universe character.