A being from Megas-Tu who brings the Enterprise to his world and is put on trial by his people for helping humans.
Lucien is a Megan, one of a long-lived species able to practise magic, who lived on Earth in ancient times before persecution drove them away. In The Magicks of Megas-Tu, the Enterprise is pulled into a vortex near the center of the galaxy, and Lucien appears on the bridge, repairs the ship and shows the crew his planet.
The other Megans fear humans and put Lucien and the crew on trial in a recreation of Salem in 1691, where his people were once persecuted. The Megans claim that Lucien is Lucifer. Kirk defends him, and the Megans relent, sparing Lucien from eternal isolation.