As discovered by Polygon, Assassin’s Creed 4 and Watch Dogs could exist in the same universe –– or the connection could be just a rather clever Easter Egg.
Apparently when players hack the Abstergo computers in the present-day setting of Assassin’s Creed 4 they can find a page about the Blume Corporation, which created the ctOS that allows players to hack in from their phones in Watch Dogs.
The brochure for the Blume Corporation comes along with comments from Abstergo personnel about the company and ctOS.
Easter Eggs or deeper connection, Assassin’s Creed 4 game director Ashraf Ismail hinted at the tie in an interview with Elder Geek at E3.
How this plays out between both Ubisoft titles is unknown, however.