Speaking to Eurogamer, creative lead Alexandre Amacio mentioned how Ezio's and Altair's story will be concluded in Revelations, whilst Desmond's story will be concluded in the Assassin's Creed game due out next December.
"Assassin's Creed is all about cycles - we have the Ezio cycle and the Altair cycle, and both of those are set to conclude in Revelations and we have the Desmond cycle, which is set to end on December 2012," he said.
"We set up a timeline with this whole end of the world plot of December 2012."
The dev team have also stated that they are going to ditch the yearly cycle of releases, giving them more time to develop future titles.