When the vortex opened a team of military personnel were sent to investigate. All who came into contact with the vortex were changed. One of those infected was a military general. Only the generals' arm was infected so the arm was amputated.
A scientist stole the arm, and when the military came to recollect the arm, the scientist injected some of the blood from the arm into his son,Johny. The military believed the child and his father dead in the fire that occurred during the raid on the home.
The boy later showed up in a plaza,in Arcadia, where he stayed until he was rounded up by the police. He had severe burns over most of his body. He had no memory how they got there or who he was. Two weeks later he was completely healed. Outside of the clothes he wore the only other possession he had was a burned block with the letter 'X' on it. He became a ward of the state and they gave him the name John Smith 24.
He was a violent teenager, but he was highly intelligent. He was sent to a psychologist. Psychotherapy, drugs, and hypnosis did nothing to bring back his memory nor quell his violence.
Eventually the psychologist falls for the boy who has become a man over the years of 'therapy'. She gives him a nickname: Jack. She eventually realizes her mistake and goes back to her other lover, crime boss, Carmine Tango. Jack decides to retake his lover by taking out his competition. Carmine is impressed with the young mans drive and potential. Jack became Carmines right hand man.
Years pass and the relationship only becomes stronger. The only thing stronger is Carmines belief in astrology. Carmine does whatever he divines in the stars. He places hits based on what he sees. He hires new muscle based on what he sees. And he has his closest friends murdered because of what he sees. Carmine orders Ziggurat to kill Jack because the "stars say you'll destroy him." Ziggurat cuts out Jack's eye, kills him, and throws his body in the harbor.
X is a vigilante in Arcadia, where he is taking down the corrupt people who seemingly hold influence on it. He killed those referred to as the three pigs, and is now relentless is in his quest to take down Mr. Berkshire, a prominent businessman and corrupt businessman. A muckraker by the name of Leigh is continuously hunting for him in an attempt to meet him. Leigh helps X after he is injured, but he uses the car as a bomb to make a scapegoat.
He attacks Berkshire and slashes off most of his face before escaping once again where Leigh follows him. In response to Leigh wishing to talk with him, he sends her a photo with one slash on it as his answer. X protects Leigh from a group of men chasing her. He put the words "turn yourself in" on the back of her slashed photo. It is revealed he did this to get her to draw the police out where he killed them. X and Leigh head to a rooftop but the surgically reconstructed, yet pig-faced Mr. Berkshire is there and attacks X.
X and Berkshire fight and he blows off X's collar to try and unmask him. X is still injured from the previous attack and tries his best to fight back, but Berkshire ends up getting the upper hand where he unmasks him. X himself then gains the upper hand as Leigh throws a fire extinguisher at Berkshire, allowing X to get the advantage. X reveals why he keeps lock on his mask: to hold himself back.
He then bites Berkshire's face. Leigh then looks over the edge at the two once more but sees X has left, but she the corpse of the now dead Berkshire with his transplanted face bitten off and his eyes removed. Leigh then finds X and convinces him that she will stay and help him.
X is known for giving criminals one chance. He does this by marking them with a slash. If they do it again he makes an X out of the slash. No one gets any more chances.