A celebrated exobiologist lost on Exo III, who transferred his mind into an android body using the technology of a vanished civilisation.
Roger Korby was a renowned exobiologist and the fiancé of Christine Chapel, who joined the Enterprise in the hope of finding him after his expedition to Exo III vanished. Kirk and Chapel find him alive in underground caverns, where he has discovered the android-making technology of the planet's long-dead inhabitants.
Korby plans to spread androids through the galaxy and creates a duplicate of Kirk, but it emerges that Korby himself is now an android, his mind transferred after he was badly injured. Confronted with what he has become, he destroys himself together with the android Andrea. He was played by Michael Strong.