The leader of the council of Stratos who refuses to accept that the Troglytes are mentally damaged by zenite gas in The Cloud Minders.
Plasus is the High Advisor of the planetary council on Ardana and lives in Stratos, the city in the clouds. In The Cloud Minders, Kirk needs zenite from Ardana's mines to stop a plague on Merak II, but the miners, the Troglytes, are rebelling against the city dwellers.
Plasus regards the Troglytes as inferior and treats their rebellion harshly. When McCoy finds that the miners' slow thinking is caused by zenite gas, Plasus refuses to believe it until Kirk forces him into a mine to prove it. He was played by Jeff Corey.