Captain Ronald Tracey

Ronald Tracey was a 23rd century Starfleet captain, who served as the commanding officer of the Constitution-class Federation starship, USS Exeter during the late 2260s. Ron Tracey was described by fellow captain, James T. Kirk as being "one of the most experienced captains in the Starfleet."
Despite his apparent experience, Captain Tracey violated the Prime Directive. Captain Tracey led an Exeter landing party to the surface of the planet Omega IV in 2268, where they inadvertently contracted the Omega IV virus and passed it along to the rest of their crew. Tracey remained on the surface while his crew died painfully in orbit, and found that the atmosphere provided him immunity to the virus. Driven to insanity by the loss of his crew and ship, and in violation of the Prime Directive, Tracey struck a bargain with members of the planet's Kohm faction and participated in their ongoing war against the Yangs. Newly armed with a few phasers, Tracey and​ his Kohm allies slaughtered thousands of Yangs.
The USS Enterprise eventually discovered Exeter and the dehydrated remains of its crew. The boarding party, led by Captain Kirk, was immediately exposed to the virus and beamed down to the relative safety of the planet's surface, where they discovered Tracey. After his crimes were exposed, Tracey shot and killed Kirk's security guard, Lieutenant Galloway, subdued the landing party, and demanded a supply of phasers from Enterprise.
Tracey erroneously believed the Omega IV virus held the key to immortality. He considered it an opportunity more important than the Prime Directive, and if missed, "...a crime against all Humanity." After his failure to enlist Kirk in his cause, Tracey and the Enterprise officers were captured by the Yangs. Despite Tracey's efforts, Dr. McCoy's research found that the unusually long life spans of the natives were the result of generations of evolution in reaction to deadly bioweapons used in the past. As such, there was no isolatable serum to extract to replicate that hardiness in other beings. The immunity is simply a matter of being exposed (for even a rather short time) to biological agents in the planet's environment, where any surviving lifeforms have developed immunity to the bio-war agents by evolution.
In a last-ditch effort to regain control of his fate in the face of this crushing reversal, Tracey played on the Yang's superstitions and tried to convince them that Kirk and his officers were evil, and must die. The Yangs matched Tracey and Kirk in combat to the death, to decide the truth of Tracey's wild claims. The intervention of an Enterprise rescue party permitted Kirk to spare Tracey's life and place the once-respected starship captain under arrest. (The Omega Glory)
==Background==
Captain Tracey was played by actor Morgan Woodward, who said of the character, "[He] was simply a good man gone bad, perhaps because of some ego-induced insanity. Captain Tracey didn't become a starship captain by being a jerk or a bad guy. It was just a good man gone bad. That's the way I tried to play him." (Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages, p. 62)
Tracey is the only Original Series character, other than James Kirk, to wear a captain's rank insignia and be seen (alive) as the commanding officer of a starship. All other active starship commanders were commodores (Matthew Decker, Robert Wesley, and Commodore Stocker albeit temporarily), while the captain of the was seen dead on the floor of his bridge in both and .
Depending on which version of the episode a viewer sees (syndicated or unsyndicated), two versions of Tracey are seen at the end of the episode; a madman or a scheming criminal who wants to still find a way out of his situation. This can be seen after Tracey returns in a dazed hysteria from the Kohm battle, learns from Kirk that there is no serum and, with his plans for a fountain of youth having been all for nothing, he orders Kirk, "Outside, or I'll burn down both your friends." In the syndicated version, Tracey appears to be a man at his wit's end, crazed from the Kohm battle, and he is taking Kirk outside to murder him in cold blood. This is assumed in the very next scene; Kirk attacks Tracey, in fear of his life. However, in the unsyndicated version, a much more complicated motive arises from Tracey removing Kirk. Once outside, Tracey appears to calm down. He explains that he must have more phasers and asks Kirk to help him. Kirk then says everyone can simply beam up, but Tracey will not go, fully aware he would face criminal charges. He then pleads with Kirk, offering to join forces with him, and asks, "If I put a weapon in your hand, you'll fight, won't you?" He then gives Kirk his communicator and lets Kirk contact his ship to ask for phasers. When Sulu refuses to beam down weapons, Tracey comments that Kirk has a well trained crew. Only then does Kirk attack Tracey, seemingly as a last ditch attempt to take him into custody and beam off the planet. (The Star Trek Compendium)
Tracey's quest for immortality, in spite of a great moral cost, was later echoed in , when Vice Admiral Matthew Dougherty attempted to harness the metaphasic radiation unique to in 2375.