Karros operated as a high technology thief for hire and led a small group of criminals that were wanted by Interpol. Karros would always fight with razor sharp claws just like Wolverine from the Marvel universe. An executive named Richard Armacost paid Karros with 40,000 credits to steal samples of an experimental growth hormone that Wayne Powers developed. Karros even agreed to cooperate with Armacost's plan to use Charlie Bigelow to infiltrate Wayne Powers' biochemical lab. When the operation failed, Karros threatened to kill Charlie unless he paid him 40,000 credits that he was owed by Armacost. Karros confronted Armacost to express his anger to him, however the conversation was interrupted by Batman who recorded the whole thing for Commissioner Barbara Gordon to hear. The conversation was interrupted by Big Time, who was Charlie that got mutated by the biochemical that spilled all over him during the robbery. During the fight, Karros fell several stories and was transferred to County General Hospital. It was assumed that Karros died.