Except for Tom Bombadil, nobody seemed to be immune to the corrupting effects of the One Ring, even powerful beings like Gandalf and Galadriel, who refused to wield it out of the knowledge that they would become like Sauron himself.
In J. R. R. Tolkien's The Lord of the Rings, Samwise Gamgee can resist the One Ring throughout the entire journey to Mordor. Even when wearing the One Ring, Sam did not give in to its influence, and he returned it to Frodo without hesitation.
He and Gandalf both state that he is the "eldest" and assuming this is true, no one person could possibly be older than time itself, save for Eru Ilúvatar. The Ring has no effect on him because the Ring has nothing to offer him; time is already immortal, and neither good nor evil.
Only Tom Bombadil was unaffected, because he wanted nothing beyond what he already had. He was master of his own land and wanted nothing more. Hobbits were largely content with what they had, but did have some malice towards their neighbours. That's why Bilbo and Frodo were not affected much, but not immune.
As for Sam, his resistance likely has to do with his innate goodness and loyalty. His love for Frodo helped him to overcome the pull of the Ring and his inner pureness was never fully pierced by the Ring.
Though Elves and Maiar had greater natural resistance to the Ring's effects, Hobbits possessed an inborn resilience to its primary means of temptation. In fact, they saved Middle-earth from Sauron precisely because they could fend off his influence better than most others.
As Johnston summarizes: What we know about Bombadil is that he is a powerful and ancient being, older than Gandalf and older than the elves, and he has no interest in “trinkets” that are used to dominate others. Although he is aware of evil, he has no fear of it.
In general, it is considered as accepted the theory that Tom is one of the Ainur, angelic beings who shaped the earth. In fact, Robert Foster's The Complete Guide to Middle-earth describes him as "a Maia 'gone native'".
The dwarves of Middle-Earth were notoriously strong willed, able to resist corruption and stay true to their purpose. Sauron had no means by which to corrupt them regardless of how he tried.
Bilbo's Compassion Protected Him From The Ring's Corruption
Luckily, Bilbo's compassion causes him to show mercy. The importance of that moment is revealed in one of Gandalf's wisest quotes when he tells Frodo that Bilbo's pity and compassion in acquiring the Ring help protect him from its corrupting power: “Pity?
Except for Tom Bombadil, nobody seemed to be immune to the corrupting effects of the One Ring, even powerful beings like Gandalf and Galadriel, who refused to wield it out of the knowledge that they would become like Sauron himself.
Galadriel, one of the greatest Elves of Middle-earth, could resist the temptation of the One Ring because of her exceptional strength of will, wisdom, and awareness of the Ring's corrupting influence.
Legolas, one of the calmer members of the group, could resist the Ring for some time, but it still would've likely corrupted him before reaching Mordor.
To go further, Tolkien wrote in Letter #131, "that anyone who used it became mastered by it; it was beyond the strength of any will to injure it, cast it away, or neglect it." Thus, no one could have willingly destroyed the One Ring, despite their best intentions.
Given these bits of information, it seems like within his realm, Bombadil would have been able to defeat the Nazgûl or at least banish them. Outside his realm, however, he wouldn't have been quite as effective in a fight against them.
As previously stated, Gandalf is a Maia and is therefore superior to Elves regarding power. Still, this isn't to say that an elf couldn't develop enough skill and power to defeat a Maia. As a bearer of one of the Three Elven Rings (Nenya), Galadriel would have an edge against Maiar like Saruman and Radagast.
Many Lord of the Rings fans also say Tom Bombadil is actually the most powerful character in all of Middle Earth, due to his apparent immortality, ability to completely resist the Ring, power over his domain, and knowledge that comes from living since the beginning of time.
It doesn't say anywhere that the Ring tried to possess Tom Bombadil and that he resisted. The Ring simply has no effect on Tom, and that's probably because Tom is a being out of space and time. He is a complete anomaly as well as an incongruity. The laws of Middle-earth almost don't apply to him.
But there's actually a long-standing fan theory of the original books, which, if true, quietly means Tom Bombadil was in the movies all along — in his true form as the Witch-king of the Nazgûl. The twist seems outlandish, especially considering Bombadil's overtly benevolent nature in Tolkien's work.
In the War of the Last Alliance, Isildur cut the One Ring from Sauron's hand, but refused to destroy it. Isildur was later killed by Orcs in Disaster of the Gladden Fields, and the Ring was lost for nearly 2,500 years. His refusal to destroy the Ring allowed Sauron to endure and remain a threat to Middle-earth.
The first is that Bilbo is a hobbit, and as such, is particularly difficult to manipulate or corrupt. Hobbits have a natural resistance to the influence of the ring, because they are fully content in their simple lives and have no desires for power or war.
Dwarves: They were too stubborn to be dominated directly, but the rings inflamed their greed to the point where they would not willingly give away their rings, and certainly not once Sauron started making war on them.
