The leader of a long-extinct race whose consciousness survived in a container, and who borrowed Kirk's body in hope of building a new one.
Sargon is one of the last three survivors of an ancient and advanced people whose world was destroyed by war half a million years ago. Their minds have been preserved in spheres deep beneath their planet's surface, and Sargon draws the Enterprise there to ask for help.
He borrows Kirk's body, while his wife Thalassa occupies Dr. Ann Mulhall's and their former enemy Henoch takes Spock's, so that they can build android bodies for themselves. When Henoch tries to keep Spock's body, Sargon helps defeat him. Sargon and Thalassa then choose to leave together into oblivion rather than take the bodies they were lent.