Kovin was an Entharan trader who dealt in weapons. He was capable of designing and making modifications to numerous weapons technologies in his lab at the Entharan colony planet in the Delta Quadrant.
In 2374, Seven of Nine accused him of violating her in order to steal her nanoprobes. She noted that Kovin stunned her and used equipment in his lab to extract nanoprobes in her system. He denied the charges, and agreed to allow Tuvok to conduct an investigation. At first the investigation revealed that there were nanoprobes present in the lab.
Fearing that he would be arrested unjustly, he fled in his ship. Tuvok and The Doctor would discover that Kovin was innocent, that when he fired a weapon to demonstrate it to Kathryn Janeway, it activated the nanoprobes. This caused a false memory in Seven about her assimilation. When Janeway hailed Kovin to tell him that they believed that he was innocent, he didn't believe them, and fired on USS Voyager. This caused an overload in his weapons which caused an explosion that destroyed his ship, killing him. (VOY: "Retrospect")