(coexisting on another dimensional plane)
Slar was a Gorn slavemaster employed by the Tholians in 2155. He was the headmaster of the salvage team assigned to strip the starship USS Defiant, which the Tholians had captured from a parallel universe and a century in the future.
During the salvage operation, the Defiant was boarded by an away team from the ISS Enterprise. When the Terrans stole the Defiant, Slar began killing Enterprise crewmembers and sabotaging the ship. Contacting Jonathan Archer, the Terran who had taken command of the Defiant, Slar promised to return stolen plasma regulators, which the Defiant needed in order to go to warp, in exchange for one of the ship's shuttlecraft. Archer refused, however, and led a security team to hunt down and kill the Gorn. Archer eventually engaged Slar in personal combat, and was victorious when he ordered Commander T'Pol to increase the polarity of the grav-plating where Slar was standing, incapacitating him. Archer then shot him to death with a particle rifle. (ENT: "In a Mirror, Darkly, Part II")