Alex Mercer, also known by his Blackwatch codename: Zeus, he the protagonist of Prototype. He was the former head researcher of the Blacklight Project at Gentek. After learning that those affiliated with the project were being systematically murdered, Mercer attempted to flee the city with a sample of his research contained in a vial. Cornered at Pennsylvania Station, Mercer smashed the vial and unleashed the deadly virus into the surroundings. This triggered a viral outbreak that eventually covered all of Manhattan Island.

After freeing the city from a deadly purge, Alex found out about his past, about who he is and who he was before, which he didn’t like at all. As the months passed, his heart got overtaken by the darkness, dominated by the Blacklight Virus, with the only purpose to spread the virus all over the Manhattan City. Now, the town is at war with Alex Mercer, trying to take him and his forces down. He has reached a point where he can turn people into evolveds, beings that have a fragment of Alex’s power, but not fully