A survivor of Sargon's ancient civilization, once his enemy, who takes Spock's body and plots to keep it in Return to Tomorrow.
Henoch is the third of the ancient survivors stored in receptacles in Return to Tomorrow, and was once on the opposite side from Sargon and Thalassa in the war that destroyed their world. He is given Spock's body while the beings build androids for themselves.
Henoch secretly intends to keep the body. He tries to kill Kirk's body while Sargon inhabits it, using a drug administered by Christine Chapel, and sabotages Spock's stored consciousness. Spock survives inside Chapel's mind, and Sargon and Spock combine to drive Henoch out. Henoch was played by Leonard Nimoy.