A renowned historian and Kirk's former teacher who imposes a Nazi-style state on Ekos and becomes a drugged figurehead in Patterns of Force.
John Gill is one of the Federation's most respected historians and was James T. Kirk's history instructor at Starfleet Academy. Assigned as a cultural observer to the planet Ekos, he stopped reporting years before Patterns of Force.
Kirk and Spock find that Gill broke the Prime Directive by reshaping Ekos on the model of Nazi Germany, believing it was the most efficient state in history and that it could be run without its cruelty. His deputy Melakon seized real power, drugged Gill and used him as a puppet Führer while organizing a campaign against the Zeons.
With help from the underground, Kirk reaches Gill and McCoy revives him enough to make a broadcast denouncing Melakon and ordering a halt to the attack on Zeon. Melakon shoots him, and Gill dies admitting that even a benevolent version of such a system leads to evil. He was played by David Brian.