Kasim

Kasim was a member of the Turkish Assassin Brotherhood, and a lieutenant under their leader Yusuf Tazim.

Kasim was one of the Assassins who first greeted Ezio Auditore da Firenze, the Mentor of the Italian Assassins, upon his arrival at the Turkish Assassin hideout. He later warned Ezio and Yusuf of a Byzantine attack on the Assassins' Galata and Bazaar Dens.

Source

 * Assassin's Creed: Revelations novel