A former Earth colony where Governor Kodos ordered the execution of thousands of colonists during a famine, a crime witnessed by the young James T. Kirk.
Tarsus IV was an Earth colony whose food supplies were destroyed by an exotic fungus, leaving its population facing starvation. Governor Kodos declared martial law and ordered the execution of about four thousand colonists so that the remaining people could survive until relief arrived. When the supply ships came, Kodos was presumed dead and earned the name Kodos the Executioner.
The Conscience of the King reveals that the young James T. Kirk and Kevin Riley were among the survivors who saw Kodos. Years later, Kirk's suspicion that the actor Anton Karidian is Kodos brings the massacre back to the surface, along with a string of murders of the remaining witnesses.