Rokon was a Kastrian king. His subject, Eldrad wanted them to pursue galactic conquest, but Rokon was unwilling to do so. In retribution, Eldrad destroyed the spatial barriers, leaving Kastria a victim of solar winds that made life on the surface impossible. Eldrad was sentenced to death and Rokon oversaw his execution. He ordered Commander Zazzka to activate the obliteration module in which Eldrad was confined at nineteen spans from Kastria, rather than twenty-five, as he feared solar winds might leave them unable to control the craft.
Rokon knew this premature detonation might have allowed Eldrad to survive and so had the city booby trapped. (TV: The Hand of Fear) He assigned the executioner Mulkris to gather the fragments of Eldrad, scattered across space, and place them in a stasis field. (AUDIO: Eldrad Must Die!)
Rather than face a life underground, the Kastrians chose, what Rokon called, "final oblivion". They also had the race bank destroyed so that, if Eldrad returned, he could not restore the species from there and wage war as their king. Rokon created recordings of himself imparting this information which Eldrad saw when he returned to Kastria one hundred and fifty million years later. He found Rokon's body and considered himself cheated of his destiny - to overthrow the king. (TV: The Hand of Fear)