The following is a list of Tarsus IV inhabitants.
These survivors were among the four thousand (half the population) not murdered by Kodos in 2246. Some of them were children at the time, and watched their parents die.
Of those survivors, there were nine witnesses who who would have been able to identify Kodos visually, of which four unidentified witnesses were murdered sometime before 2266 by Lenore Karidian to keep them from testifying. Before they could be listed by the USS Enterprise's computer, James T. Kirk interrupted it upon hearing Kevin Riley's name on said list. (TOS: "The Conscience of the King")
These victims were murdered by Kodos in 2246. They were chosen based on Kodos' own theories of eugenics. Though their deaths were physically painless, they were nonetheless traumatizing to those left behind. (TOS: "The Conscience of the King")
Kevin Riley's parents
The parents of Kevin Riley were inhabitants of Tarsus IV in 2246, when they were sentenced to death by the colony's governor, Kodos. Riley was haunted by the events, and decided to avenge his parents' deaths when Kodos (disguised as Anton Karidian) visited the USS Enterprise in 2266. (TOS: "The Conscience of the King")