(real name unknown)
Assassin X is a ninja and an operative working for Hammer. He is blind but is still able to sense everything around him.
Much of Assassin X's past is unknown. He works for Hammer and was like a brother to Agent Zero. They even had the same sensei. At some point, for reasons unknown, Zero left Hammer and later began working with Deuce. The two ninja's hated each other after that.
The two met again deep in the lower levels of the fortress on Hammer Island, where Assassin X was killed.