User blog comment:D. Cello/Assassinews 10/19 -- ACR new info/@comment-78.147.130.139-20111024182209/@comment-4043223-20111025163627

Desmond is a playable character as he will be interacting with the black room (in the form of interactive puzzles) in order to unlock his and his ancestors memories. We do not know if Desmonds memories will be interactive or simply be viewed by us the players (and Desmond of course).