The One Ring is, of course, the most important object in the entirety of The Lord of the Rings. Forged by the Dark Lord Sauron, it contains a great deal of his power and essence and is thus key to his quest to bring all of Middle-earth under his personal domination. Since its forging in the Second Age of the world, it has known a number of bearers, as various individuals have sought to claim it and make its power their own.
Of course, none of them are able to fully master its power, and it ultimately inflicts damage on all of them until its ultimate destruction in Mount Doom.
Frodo
It probably goes without saying that Frodo is the most important of those that bore the Ring. It was he, after all, who was tasked with throwing it into the Cracks of Doom and destroying it forever. While he accomplished his task to a degree - it was Gollum, after all, who bit off his finger and tumbled into the fire - it came at a terrible cost. For the rest of his time in Middle-earth, Frodo was haunted by the specter of his past until he at last was sent across the Sea in the hopes that he might be restored.
Sam
A lot of people tend to forget that Sam - dependable, lovable Sam - was also one of those who bore the Ring, though for a brief time. He took it upon himself when he believed that Frodo had been slain by the monstrous spider Shelob. The Ring, however, didn’t have as much hold on him as it did on many others, mostly making him believe that he might be able to remake Mordor as a land of plenty. Eventually, he returned the Ring to Frodo.
Those who have read the Appendices to the novel, however, know that he too was allowed to journey across the Sea many years after Frodo departed.
Bilbo
Were it not for Bilbo seemingly finding the Ring while lost in the Misty Mountains, the events that would later change the course of history in Middle-earth would never have happened. Bilbo had the Ring for longer than almost anyone else described in the books, with the result that he also aged incredibly slowly. It did take a toll on him, however, and it was only with a supreme effort of will that he was able to divest himself of it and leave it to Frodo. For his service to Middle-earth as one of those who bore the Ring, he was allowed to journey across the Sea with the Elves.
Isildur
Poor Isildur. One of the powerful men of Numenor, he had the makings of a great and mighty king. Unfortunately, it was his doom to be present when Sauron was overthrown, and as soon as he could he cut the Ring from the Dark Lord’s finger and took it for his own. As the film shows, almost as soon as he encountered it, he felt its seductive pull. Though he should have known better, it would have taken a greater will than he had to resist its siren call, and it ultimately betrayed him, slipping off of his finger and leaving him visible to Orcs.
Gollum
Next to Frodo, Gollum is one of the most important characters to have had the Ring. Since he gained it through murder (slaying his friend and kinsman Deagol), the Ring exerted a pernicious effect on him, gradually twisting him until he was little more than an emaciated shadow of his former self. And yet, despite all of that, it was actually due to him that the Ring was finally destroyed. It’s a bit of a strange turn of fate, but it’s in keeping with Tolkien’s basic belief that goodness will always win out in the end, an optimism the films share.
Sauron
Sauron. The very name conjures up all sorts of fear and despair. How could it not be so, when he is the source of so much of the evil that afflicts Middle-earth? He is, of course, responsible for the forging of the One Ring in the first place, and he poured so much of himself into it that he is never the same until he has it in his possession once again. When, at last, it is destroyed, he becomes little more than a shadow of his former self (though it’s important to recognize that he is not, in fact, completely destroyed, since evil is never fully vanquished in the world of mortals).
Deagol
Deagol was the hobbit-like creature that had the misfortune to find the Ring in the marshes of the Gladden Fields, where it had fallen after it betrayed Isildur. Unfortunately, he wasn’t alone when he discovered it, and though he refused to hand it over to his friend Smeagol, that didn’t stop the other man from slaying him. It seems that Deagol’s fate was to be yet another of those bodies that lay strewn in the wake of this powerful object that had the potential to change the fate of Middle-earth.
Tom Bombadil
Many readers might forget that Tom Bombadil was also one of those who held the Ring, though it was for a very brief period of time. When Frodo handed it to him and he put it on, he did not disappear. Though there is no specific explanation given for this, it would seem that his lack of invisibility stemmed from the fact that the Ring had no hold over him.
In fact, during the Council of Elrond, there were those who thought that he should take custody of it, though Gandalf reminded them that it would be dangerous since Bombadil might well throw it away out of carelessness.
Gandalf
Though it isn’t revealed until the end of the story, it turns out that Gandalf is actually one of the bearers of the three rings that were made for the Elves. More than that, though, he also held the One Ring itself for a very brief time, when he returned to the Shire to determine whether or not it was, in fact, the Ring that had been made by Sauron.
