User blog comment:MeDeoPal/Assassin's Creed IV Story Ideas (Ye Be Warned Of Ye Spoilers)/@comment-67.185.156.169-20121104042108

You clearly missed one of Shaun's emails near the end of the game:

The EYE-ABSTERGO launch was indefinitely put on hold due to Vidic's death, and their inability to locate any Pieces of Eden. Apparently, they lost all their leads. (how is beyond me.)

Anyway, there is no doubt the new threat to humanity is the awakened Juno. She is pissed off. As for what other time periods AC will visit now, who can say?