Kadar Al-Sayf

Kadar is a novice Assassin, the younger brother of Malik. From Kadar's words in Solomon's Temple, it is evident that he admires Altaïr's skill and rank.

Kadar was killed near the beginning of Assassin's Creed, but it is not clear where and when- at first it seems that he is killed in Solomon's Temple, but it was speculated he was perhaps the hostage Robert de Sable had executed outside the Assassins' Fortress. However, the hostage is not wearing the robes of a novice that Kadar was wearing in the temple. Malik himself had said that Kadar died at Solomon's Temple, but he may have been mistaken, and Kadar may have been simply taken hostage. Malik, already embittered toward Altaïr for his breaking of the Tenets, is infuriated by his brother's death. He believes that without Altaïr's arrogant actions, Kadar would have lived, and he (Malik) would not have lost his arm.

Assassin's Creed: Altaïr's Chronicles

There is another assassin named Kadar that appeared in Assassin's Creed: Altaïr's Chronicles prequel.