It does seem that in this particular leak, Aiden Pearce will be part of your world this coming May 27th, although the Xbox LIVE store could very well have pencilled in different plans for other folks. Needless to say, the listing is no longer there for download, and there are no additional details or information made available to the masses to date. It did however, share a 23GB download size that could or could not be the size of the installation when the game finally rolls out.
Apart from that, there is also a description of Watch Dogs that reads, “You are Aiden Pearce, a brilliant hacker but also a former thug, who’s criminal past lead to a violent family tragedy. In a world led by technology, you will be able to hack systems to stop traffic lights, detonate gas lines, turn off the electrical grid and more. The city of Chicago has become the ultimate weapon for a man bent on revenge.”