Thomas in 2266
Doctor Thomas Leighton was a male human in the 23rd century who was a food technologist and scientist who had witnessed the massacre of the colonists on Tarsus IV by its crazed governor, Kodos, in 2246.
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")