Landru is the main antagonist of the Star Trek episode "The Return of the Archons".
He was portrayed by the late Charles Macauley.
Landru was the ruler of Beta III thousands of years ago. He had guided his people out of war but was convinced they needed his continued guidance. He therefore constructed a machine that contained all of his knowledge to rule over them in his place. The machine used a projection of him as a public face. It had mental dominance over almost all the planet's population, keeping them in a state of peace and tranquility but also letting them release their passions and violence on each other in designation periods. Its will was enforced by robed lawgivers.
The Starship Archon came to the planet but its crew were either killed or came under Landru's control. The Enterprise visited the planet to investigate but the first two crewmembers to beam down, Sulu and O'Neil, fell under Landru's control. Kirk beamed down with a larger party but they were also captured by Landru. McCoy and another member of the team were brainwashed by Landru but an undercover rebel, Marphon, faked the process on Kirk and Spock.
Kirk and Spock confronted Landru in his chamber and blew away the wall to reveal his true nature as a complex machine. Although Landru was able to disable their weapons, he was unable to fully process Kirk and Spock's insistence that he was slowly killing the planet's people by denying them free will and creativity. His increasingly feeble protests ended with him overloading and ceasing to function.