A new multiplayer trailer of Assassin’s Creed: Brotherhood was shown at Comic Com 2010. In AC: Brotherhood, you’ll see the return of Ezio and the continuing struggles of the Assassins vs the Templars. Expect almost everyone that you met in ACII (but didn’t kill ) to return, albeit through deepened relationships.
Remember that room filled with Animi (Animuses?) during the escape scene at the beginning of ACII? That’s the Templar-controlled company’s training ground for new, counter-assassins. They’ve been uploading the skills that actual Assassins like Desmond have been unlocking into their most adept pupils, and their training simulation is the multiplayer component of the game.