i think you mean 3rd which is brotherhood your ezio.
Brotherhood was the 3rd installement in the series but assassins
creed 4 has been announced now and it is called "assassins creed
revelations". revelations is the final chapter in Ezio Auditore's
story. There for you will most probably use Ezio once again.
Another person: Here is a list of all the ac games in order from
2008 to 2012
Assassins Creed (You are playing the fictional character of
Altair Ibn La-Ahad in this game)
Assassins Creed 2 (You are playing Ezio Auditore Da Firenze)
Assassins Creed Brotherhood (Ezio again)
Assassins Creed Revelations (Ezio)
Assassins Creed III (Final Installment of the Assassins Creed
series, in which you will be portraying Connor Kenway and his
father)