In Assassin's Creed II, the Florentine Assassin who becomes the main hero is Ezio Auditore da Firenze.
Ezio is introduced as a young nobleman in Florence during the Italian Renaissance. After a political conspiracy destroys much of his family, he is drawn into the conflict between the Assassin Brotherhood and the Templars. His campaign follows his growth from an inexperienced young man into a highly capable Assassin.
The game covers more than one period of Ezio's life and takes him to locations including Florence, Venice, Forlì, and Monteriggioni. Leonardo da Vinci assists him by interpreting pages of Altaïr's Codex and creating devices based on the designs.
Ezio's full name is important because several later games feature him, including Brotherhood and Revelations. Those titles continue his story rather than introducing different heroes named Ezio. Connor, Edward, and Arno belong to other Assassin's Creed protagonists.