Al Mualim , sometimes known as The Old Man of the Mountain or by his historical name Rashid ad-Din Sinan, is the hidden true main antagonist of the 2007 video game Assassin's Creed. However, Altaïr only finds out about him being a Templar at the very end of the game. He was the Mentor of the Assassins until he was defeated by Altaïr, who became Mentor in his place.