The Repeller was a mercenary who wore a suit that repelled all matter. In reality, he was Dr. Suzuki, a scientist working at Wayne-Powers Medical Research.
Together with Dr. Blades, Suzuki strove to improve isolation environments for those born with a defective immune system. They developed the ISO field generator rings which created a protective aura allowing its user to interact in an outside environment.
Dr. Suzuki saw the lucrative possibilities of the diagravitational rings, but considered that Blades was too short-sighted to understand it. So, he purchased power-boosting servo circuitry, forging Dr. Blade's signature, and secretly enhanced the power of the Rings. Then, Suzuki decided to make a profit out of this powerful weapon, and became a burglar for hire.
At some point he was hired by a terrorist cell to steal three rare Isotopes ― Alpha Sterilium, Beta Sterilium, and Gamma Sterilium. He stole the Alpha Isotope from a university. The Beta Isotope was kept in a high security research lab, stored in a meta-caloric liquid. This time, Batman stepped in and tried to foil him, but the Repeller easily deflected anything he could throw at him, and escaped.
On the next day, Bruce Wayne and Terry McGinnis paid the laboratory a visit, and Dr. Suzuki cordially gave him a tour of the lab and told him about the ISO Rings. The excursion was, however, cut short by Dr. Blades who admonished Suzuki for showing Bruce their research.
Later that night, the Repeller met with his contacts ― Makeba and Muscles ― in Gotham Steel + Ore, and delivered them the Isotope Beta Sterilium. This time, he charged double the fee than that for the Alpha Sterilium because of his running into Batman.
However, he assured the terrorists that next time he'd kill Batman. The Repeller headed off to the Blüdhaven Nuclear Facility to steal the final component. As expected, he was intercepted by Batman who snared him in titanium straps, but still managed to break free. The Repeller then pushed Batman off a cliff with a blast of repelling energy. Convinced that Batman had drowned, the Repeller stole the Gamma Isotope and headed off to his laboratory.
There, Suzuki called his employers to give them the good news. He suddenly heard a noise and found Irene hiding behind a closet. Before he could do away with her, Dr. Blades came in. Suzuki moved on to kill Dr. Blades and Irene, but was thwarted by Batman. A battle ensued, and Suzuki hurled Batman into a hangar. Even though Suzuki had the upper hand, Batman activated a giant turbine that generated so much noise that Suzuki was forced to cover his ears; the aura stopped him from doing so effectively, and he had to deactivate it, allowing Batman to apprehend him.
Donning the enhanced ISO field generator rings, Suzuki was virtually unstoppable and invincible. He had an impenetrable aura that enabled him to withstand any impact, and survive in any kind of aggressive environment. Suzuki could also concentrate and channel energy down his palms, thus emanating powerful repelling and destructive bolts. Finally, the anti-gravitational properties of the Rings allowed him to levitate and levitate other people and objects.