Domhnall Kovac is an MMA training gym owner and a white supremacist using the gym as a cover for recruitment centers. He was one of many violent racists across North America planning far-right terrorist attacks, leading to undercover operations at his gym and others. He was also a suspect in the assaults of four Black men. When Brandon Arnou joined his gym, he eventually indoctrinated him into his racist and neo-Nazi ideology.
When gay Black comedian Ellis Joyner was murdered on the subway, Kovac was questioned when the killer was found to be wearing his gym's uniforms and displaying his gang's tattoo. After one of his members, Brandon Arnou, was identified as Joyner's killer, Kovac was called to the stand by the prosecution to show that Arnou was indeed a fellow racist. (L&O: "Facade")