A lieutenant commander who leads the Enterprise security teams hunting the creature killing miners in the tunnels of Janus VI, and later guards the wounded Horta from the vengeful colonists.
Lieutenant Commander Giotto heads the security detachment in the first-season Original Series episode The Devil in the Dark. He was played by Barry Russo, who returned in the second season as Commodore Wesley.
When the Enterprise answers the distress call from the pergium mining colony on Janus VI, Kirk puts Giotto in charge of the armed search parties sweeping the lower levels. His men carry phasers adjusted by Spock to be effective against silicon, and one of them is killed by the creature.
After Kirk and Spock discover that the Horta is an intelligent mother protecting her eggs, Giotto finds himself holding back Chief Engineer Vanderberg and his miners, who overpower the guards in their rush to kill it. He stands by as Kirk explains the truth and peace is made.