User blog comment:Nardei99/AC4 Possibilities/@comment-197.122.198.35-20120310152152/@comment-1888015-20120311004225

Ubisoft have stated that history is their playground, so whatever time periods they use do not have to follow a pattern. In the case with Desmond, the ancestor whose memories he explores has to have some bearing on the First Civilization and with AC3, his location in the world.

Considering that AC3 is the last in Desmond's trilogy, from AC3 onwards, they could have any protagonist from both the future and the past as part of their games.