User blog comment:Hassan-i Sabbā/Assassins Creed And Watch Dogs Connection/@comment-1153722-20140718100815

I'm afraid that this has been discussed multiple times already before and after the release of Watch Dogs, but Ubisoft employees (more specifically, Darby McDevitt) have confirmed that none of their franchises are set within the same universe. While Darby would like for there to be a 'Ubiverse', the creative teams of each franchise are doing their own thing and they're not part of one larger scheme.

So the easter eggs in Assassin's Creed IV: Black Flag and Watch Dogs relating to one another are just that – easter eggs. While Blume and CtOS are established to exist within the AC universe because of it, as is Olivier Garneau in the WD universe, none of the events from WD are known to happen within the AC universe and vice versa.

This discussion already came around when an old facility with Abstergo symbols and letters relating to the Pieces of Eden appeared in Far Cry 3, and I fear the conclusion remains the same.