Inquisitors
The Inquisitors were the rulers of a class M planet in the 23rd century. They wore black robes and hoods. Any who dared to oppose them was arrested and taken to their castle, where they were brought before their leader, the Grand Inquisitor, and tortured in their interrogation chambers until they confessed to being in league with the Dark One. The Inquisitors were thus greatly feared by the people over whom they ruled.
In 2268, the Inquisitors seized the radio and other equipment of the crashed Federation shuttlecraft Galileo and took it to their castle for the Grand Inquisitor to examine. This was witnessed by the shuttlecraft's crew, James T. Kirk, Spock, Leonard McCoy, Pavel Chekov and Claire. While Kirk and McCoy made contact with the rebels, Spock, Chekov and Claire attempted to recover their radio, but the Inquisitors captured them and demanded that they show them how the machines worked, torturing Spock when he refused. Spock resisted being tortured, but agreed to talk when the Grand Inquisitor threatened to torture Claire instead. Just as Spock finished repairing the radio, Kirk and the rebels arrived to free the officers and capture the Inquisitors, presumably ending their rule. (TOS comic: "Day of the Inquisitors")