He commanded the MA-12-class cruiser GCS Gress'sril that destroyed the Federation outpost on Cestus III. S'alath was forced by the Metrons to battle Starfleet Captain James T. Kirk in order to settle their differences. Kirk astounded all by besting S'alath and then letting him live, refusing to allow the Metrons to goad him into committing what he saw as murder. This impressed both the Metrons and the Gorn, and S'alath would often recount the honor of the combat and take pride in the scars from Kirk's cannon-blast. S'alath grew old and eventually began to suffer the effects of old age on his mind. He devised an elaborate death for himself, living out the end of his days on a remote, deserted planet fighting holograms depicting Kirk. (TOS episode & Star Trek 2 novelization: Arena; FASA RPG modules: Star Trek IV Sourcebook Update, Demand of Honor; TOS - Unlimited comics: "Dying of the Light", "The Veteran", TOS video game: 25th Anniversary)
Following the Gorn captain's encounter with Kirk, he helped to negotiate the Frontier Accord with the Federation, but later returned to Metron space. In 2373, the Gorn captain approached Benjamin Sisko to help preserve the legacy of the Metrons. The Gorn captain later took Sisko to the site of his encounter with Kirk, reflecting that if he had faced Sisko he would have been more careful. (DS9 - Strange New Worlds I short story: "Where I Fell Before My Enemy")
This character was referred to as S'slee in the FASA Corporation RPG module Demand of Honor, and was given the alternate name S'alath in Marvel Comics from the Star Trek Unlimited series. The CCG set These Are the Voyages called this character S'salk. The Last Unicorn Games RPG sourcebook Planets of the UFP called him Rheuzz'r. It's possible that the various names all form part of some long-form name or surname. The Typhon Pact novel series from Pocket Books has since reaffirmed the Star Trek Unlimited name of S'alath within the novel-continuity. The more recent Star Trek Adventures Core Rulebook calls the Gorn captain Arijog. The even more recent Beta Quadrant Sourcebook goes back to calling him S'slee.
The game Star Trek: Attack Wing uses images of the Gorn captain to represent the characters S'sesslak and Lahr. It's unclear which of these, if any, is supposed to be the Gorn captain who fought Kirk.
The character of Commander Raaskaa was intended to represent this character, but the licensing office at Paramount Pictures requested that the reference be removed from TOS - The Return of the Worthy comic: "Great Expectations!". The character was recolored as a scarlet lizard, and spiky black hair was drawn onto it. The editors intended for this to change the species, and several pieces of dialogue were altered to call the scarlet Gorn a "Lath". However, the word "Gorn" was included in the issue several times as the editors had missed several mentions that were supposed to be altered.