Thomas in 2266.
In 2266, Convinced that Kodos had survived his apparent death and was now disguised as Anton Karidian, the actor, Leighton diverted the USS Enterprise. James T. Kirk was also a survivor, and Leighton wanted confirmation. He was later found dead by Kirk, killed by Karidian's daughter Lenore Karidian to keep his knowledge silent. (TOS episode: "The Conscience of the King")