At first appearance, Carter was everything a student could be: smart, athletic, class president. Yet at home he suffered constant harangues from his cold-hearted mother, who was constantly pushing him to succeed and be first in everything. Inside, he was morbidly sensitive about his reputation and his sense of achievement.
At some point he adopted the alias "Terminal" and adopted a frightening costume resembling a weird cross between a zombie and an escaped mental patient. Before long, he had a gang of Jokerz under his personal command, whom he dominated through his intelligence and the force of his personality. In part, this may have been his way of rebelling against his mother's strict authority. On the other hand, it was also his unconscious way of lashing out at a world that his mother portrayed as cold and unforgiving to anyone who wasn't "the best."
Later, he got the idea of using the Jokerz to further his own agenda. After he placed second in the standardized GATT test, behind Maxine Gibson's perfect score, he and his Jokerz invaded the high school at night to delete the test records. During his search of school records, Terminal also found that Max was the leading candidate to be class valedictorian. He tried to delete those records as well, but his access was blocked. He saw no way to his goal of being first other than to remove Max.
One night, when Max was working late at school, Terminal had his Jokerz appear outside the school to lure Batman away, then reprogrammed school robots to attack Max inside. Batman arrived back, narrowly saving her. Later, Terminal and his thugs followed Max to a park where she was due to meet Terry McGinnis, and ambushed her. Batman arrived to save her again, and in the ensuing fight, Terminal fell into a fountain and his makeup was washed off. Carter was arrested. Hearing the news, his fellow students pronounced that they had always known he was a loser. Terminal's actions inadvertently led to Max discovering Terry's secret identity as Batman.
While in juvie, Carter participated in unusual therapy sessions to help in his rehabilatation. Carter's psychiatrist Dr. Sheridan conducted unconventional methods of channeling one's inner demons and then expelling them. For Carter, he was instructed by Dr. Sheridan to use a gun and shoot a portrait that bears a resemblance to Carter's alter ego, Terminal. Carter gathers his courage and fires at the portrait thereby killing any trace of Terminal (metaphorically that is). Dr. Sheridan's precedence behind this therapy is the subject has a law abiding persona that comes into conflict with a criminal element. By shooting at the representation, Carter's mental state begins to heal psychologically and become the dominant persona while the Terminal persona is left for dead.
Before the session could conclude, a group of mentally disturbed teens start a riot throughout juvie hall. Terry arrives as Batman and takes down the escaping inmates. When he reaches Dr. Sheridan's office, Terry sees Carter guarding Dr. Sheridan from two escaped inmates. Carter and Terry defeat the last of the inmates before the guards arrived. In light of Carter's heroics, Dr. Sheridan speaks on Carter's behalf during his parole hearing and the judge deems Carter mentally capable to rejoin society. Carter goes back to Hamilton High School to finish his education but he isn't greeted warmly by everyone. Terry welcomes Carter back to high school and Maxine accepts Carter's apology for trying to kill her. Her decision to accept the apology was based on Terry's analysis of Carter during the riot at juvie hall.
Afterwards, Carter is taken by surprise when his locker explodes in his face. Terry and Maxine are shocked when they see Carter's face covered with different colors of face paint. All three of them realize that Terminal's old crew has learned of Carter's release and they want him to rejoin the Jokerz. Later that same night, Terminal's crew kidnap Dr. Sheridan after rigging his car to release a knock out gas when he started his car then they kidnap Max. Both Terry and Carter hear about the kidnappings so they decide to head to downtown Gotham where the Jokerz usually congregate, to get answers. Terminal's crew eventually shows up and Carter tells Terry to run in order to get help. Terminal's crew takes Carter back to their hideout where the hostages are being kept. Unbeknownst to any of them, Terry tailed the crew as Batman while in stealth mode.
At the hideout, Carter makes a shocking revelation in front of Sheridan and Maxine. It turns out that Dr. Sheridan's therapy caused Carter's mind to split into two personalities and the Terminal persona became the dominant mental state. The Terminal persona staged Carter's rehabilatation, used the riot to his advantage, and told his crew to kidnap Max along with Dr. Sheridan in order to draw out Batman. Terminal anticipated on Batman showing up so he orders the crew to shoot up the entire hideout. Batman rounds up Terminal's crew and faces off against Terminal. Dr. Sheridan tells Batman to reach out to Carter's subconscious in order for both personas to fight for the dominance of Carter's psyche. Batman wipes away half of Terminal's painted face and forces Terminal to look into a mirror. Suddenly, both personas fight amongst each other for control and in the end, Carter drops to the floor after having a mental breakdown. Now, Carter resides in Arkham Asylum where he must contend with the Terminal persona just like Harvey Dent had to overcome Two-Face.