Karth was a 23rd century Eldorian man. He served as a commander in the Eldor Space Service as the CO of the warship Lebron.
History
In 2265, the Eldor Space Service dispatched Karth on a mission to end an interplanetary war with Norus with a strategic strike on Norusian Central Control. While exploring the sector, the Federation starship USS Enterprise encountered the Lebron. Karth and two fellow officers visited the Enterprise and met with Montgomery Scott. Karth was aware that Norusians were holding James T. Kirk and Spock captive on Norus. He told Scott that the Enterprise would soon be within range of Norusian planetary defenses, but that his ship was fortified against them. He proposed that Scott's rescue party for Kirk and Spock join Lebron during its ground assault.
Karth's strike ended the war and aided Scott in rescuing the Starfleet officers. (TOS comic: "Menace of the Moloth")