Infiltration Unit Zeta was built by the NSA. His mission was to discover information about terrorist organizations by killing a target and taking over his life.
While on a mission, Zeta discovered that one of his targets was innocent. He decided that he no longer could kill, as any one of his targets could be innocent. The NSA thought that Zeta had been reprogrammed by the terrorists that Zeta was sent to infiltrate, so the set out to destroy Zeta before he destroyed anyone else.
While Zeta was fleeing from the NSA holographically disguised as a teacher at Hill High School, Batman discovered Zeta's true identity after Agent Bennett fired a laser at Zeta's holo-projector. When Max Gibson was kidnapped by Zeta, Batman intended to destroy Zeta, but changed his mind after Zeta saved his life. Max convinced Zeta that killing is not right, even for protection. Zeta had removed all of his weapons, and had vowed never to kill again. Reluctantly, Batman helped Zeta escape from the NSA, although he still was not sure that Zeta would be able to overcome his programming to kill.
Zeta decided to call the NSA directly to try to convince them that he no longer had a desire to kill. The NSA were still certain that Zeta's strange behavior was a result of reprogramming rather than sentience, so they sent agents out to try to capture Zeta. Zeta escaped and had managed to hide from the NSA until a laser shot forced him to reveal himself while protecting an escaped orphan named Rosalie Rowan. Badly damaged, Ro helped Zeta escape the NSA agents. Ro agreed to help Zeta find the scientists who created him, and in return Zeta vowed to help Ro find her family.
In his search for his creators, Zeta found one of the scientists responsible for building him. After Zeta saved the scientist's life, it was revealed that the man who designed Zeta was Doctor Eli Selig. Zeta and Ro then decided that Dr. Selig was their best chance to convince the NSA that Zeta was peaceful.
Zeta met a young genius named Bucky who had invented a remote control that could control any machine with the proper schematics. He used the remote control to force Zeta to attack the head of the school Bucky was attending after he passed Bucky's remote control off as his own. After a struggle, Bucky's remote broke in half, and Ro used the other remote control to keep Zeta from killing the man, but the man had already confessed. He was subsequently fired, and Ro broke the other remote control. Bucky promised that he would not use his remote to control Zeta again.
While ordering parts from the classified NSA infiltration unit order website, Zeta had discovered that another infiltration unit, IU7, was going to assassinate a weapons dealer. Zeta couldn't allow that to happen, so he disguised himself as the weapons dealer in an attempt to help him escape. Bucky tried to control IU7 with his remote control, but IU7 had an override program installed. He used the remote control to control the contruction equipment instead. After IU7's attempts to escape accidentally caused the weapons facility to explode, IU7 was temporarily disabled. When IU7 rebooted and restored his mission objectives, a memory of the weapons dealer morphing into Zeta caused IU7 to switch his mission objective to destroy Zeta.
IU7 hunted down Zeta in a mall, and had taken up the appearance of Zeta in human form. The mall was destroyed, and the news reported the incident as a "war zone". Bruce Wayne was watching the news and had downloaded the malls security cameras which seemed to point towards Zeta as the cause of the destruction. Thinking that he had misjudged Zeta when he let him go, Batman went to find Zeta to take him down for good. Ro was hurt in the blast, and was in the hospital. Batman found Zeta there, and thought that he had come to kill Ro. Batman was in the process of destroying Zeta when it was revealed that IU7 was behind the mall disturbance. Zeta decided to give his life to save the lives of Batman and Ro by pushing himself and IU7 into a high powered CAT-scan machine, which would cause their circuit boards to become dislodged from their metal bodies. Batman saved Zeta at the last minute with a grapple, and IU7 was turned into a pile of scrap metal.
Zeta is a machine, but he has a conscience. He is relentlessly cheerful, and because of his analytical mind, he does not understand the concept of sarcasm. Ro is the exact opposite, as she is sarcastic and pessimistic. This has often led her to want time away from Zeta, but it also has helped her to become less withdrawn. They get together just like brother in sister in the sense that they learn from each other, and although they don't understand each other at times, they would do anything for one another.
Powers & Abilities
Zeta has a holo-projector which allows him to appear to be anyone or anything he desires. He can also change his size, which allows him to appear younger or smaller than he really is when seen in his regular synthoid state.
He is strong and durable, and his arms and legs can be extended to considerable lengths. His fingers can be used as hooks when his arms are extended, and are strong enough to penetrate metal.
Zeta was originally equipped with a full arsenal of destructive weapons, such as a grenade launcher, at least six pistols and a plasma cannon. After his first encounter with Batman, he discarded all of these weapons except for a laser torch which he uses to cut through metal and wire.