Ezio Auditore is the Assassin's Creed protagonist who serves as a Master Assassin in Constantinople.
In Assassin's Creed Revelations, Ezio travels to Constantinople, the capital of the Ottoman Empire, while searching for Altaïr's lost library keys. He becomes involved with the local Assassin bureau and works alongside Yusuf Tazim.
Ezio first appeared in Assassin's Creed II and later returned in Brotherhood and Revelations. Constantinople is the historical name used for the city called Istanbul today, although the game is set in the early sixteenth century, before the modern name became standard. The story also alternates between Ezio's life and Altaïr's final years.