Emile Dorian was a rogue geneticist, and one of the earliest forerunners of splicing.
Emile Dorian originally worked as a geneticist in Gotham City. He was obsessed with cats and decided to do experiments to enhance their feline qualities. His earlier experiments were crude in nature, resulting in harmful permanent mutations of these cats, as Kirk Langstrom showed Batman a crippled cat which, as Langstrom put it, was one of the "good doctor's" earlier works. Dorian soon developed a mutagen called T-99 which improved his experiments, however by this time the scientific community had ostracized him, given that he had earned the reputation for animal cruelty and unethical experimentation. Dorian decided to move out to an uninhabited island, where he continued his experiments out of the immediate reach of the law. He had managed to create Garth, a genetically-altered gorilla and later Tygrus, a half-man, half-tiger hybrid, with cunning and strength augmented attributes, whom he described as the pinnacle of his art.
When Tygrus was feeling lonely, Dorian decided that he should find, or better yet, create for him a soul mate. He chose Catwoman and sent Garth to kidnap her. Garth took her to the island and Dorian subjected her to splicing. As a result, Catwoman was transformed into a half-lady, half-cat creature. However, Batman investigated Catwoman's disappearance and tracked her to Dorian's island. Upon arriving, Batman witnessed Catwoman's new form and attempted to save her, but Dorian sent Tygrus to kill him. When Tygrus learned that Dorian had tricked him, he turned on his master. When the laboratory exploded, Tygrus saved Dorian and delivered him to Batman and Catwoman. Dorian was presumably later handed over to the authorities.
Emile Dorian also appeared in the spin-off comic Batman Adventures. In issue 21, "House of Dorian", Emile escapes Arkham and enlists the unwilling Dr Langstrom (by forcibly turning him into Man-Bat) to capture Batman and Selina Kyle. His act of vengeance is, however, interrupted by the reappearance of Tygrus and the werewolf Anthony Romulus, the latter of which wants Dorian to revert him back to humanity. Man-Bat, Tygrus, Dorian and Romulus are all apparently killed in an explosion that ensues, although Dr Langstrom is later seen in "Chemistry" to have survived.