Isildur, son of Elendil, is Aragorn's ancestor who failed to destroy the Ring when given the chance. Aragorn recognizes that a sense of weakness runs in his blood, and he's subsequently terrified that he will succumb to the same fate as Isildur.
Aragorn wasn't afraid to fight. He wasn't afraid to die. Basically, he was afraid to lead, because he was afraid he would fail (those under his rule). Aragorn was the descendant of Isildur, High King of Gondor.
He Lacked Self Confidence. Though he was one of the most courageous warriors of the Third Age, Aragorn lacked confidence in himself. Tolkien's novels made this clear, with Aragorn blaming himself for many of the tragedies that befell his friends during the course of the story.
Bloodlines are very important in Tolkien's stories, and it makes a lot of sense that Sauron would fear the great-grandson of the man who cut off his hand. Aragorn carried the blood of Numenor with him. His genetic connection to the heroes of the Second Age established him as a dangerous opponent of Sauron.
Bottom line, Aragorn was not factored into their calculus. They were looking for Hobbits, not a Numenorean strongman who at that point, they had little to no clue who he was. The effort it would take to kill him was more trouble than it was worth, so….
In his notes, Tolkien remarks that Sauron saw Galadriel as his equal. Add that to the fact that she's untrusting of Sauron (yes, even when he's in his Annatar guise) and an unwavering, single-minded force, and it's more likely than not that Sauron feared Galadriel — or the potential she held to upend his plans.
Though wizards are technically Maiar, they do not possess all the same abilities in their wizard forms. This is why, despite Balrogs and Sauron also being Maiar, Gandalf wasn't evenly matched in his wizarding form—especially as Gandalf the Grey.
Meanwhile, a few faithful Númenóreans, led by Elendil, were saved from the flood, and they founded Gondor and Arnor in Middle-earth. Sauron still considered them his hated enemies and he launched a pre-emptive attack on Gondor in S.A. 3429.
He died at the age of 210, after 122 years as king. The graves of the hobbits Merry and Pippin (who had died in Gondor 58 years earlier) were set beside his. He was succeeded on the throne by his son, Eldarion.
WEAKEST: Hobbits are one of the weakest races on middle earth. Most can be defeated by simply ruining their lunch. Hobbits are charming and valuable people but not a very strong race.
However, he does not possess the ability to live forever, and he cannot choose to be mortal or immortal like Arwen, the half-Elf he loves and eventually claims as his wife. Because Aragorn is mortal and Arwen chose to remain in Gondor and become mortal, their son, Eldarion, is mortal as well, despite his Elven lineage.
Legolas doesn't appear to have any hesitation in his actions throughout the films, but it's clear that his blood runs cold when a Balrog appears in the Mines of Moria. Their connection with the ancient foe known as Morgoth makes Balrogs far more fearsome than other enemies in the eyes of Elves.
Take note, then, that at the root of Gandalf's quest is fear -fear of Sauron in particular. We are not told exactly why -but Sauron is a fellow Maiar, an angelic being who chose to follow Morgoth at the beginning.
He will fight in the Last Battle against the Valar and their allies, but will ultimately be slain by Túrin Turambar, the Man he cursed. By finally defeating Morgoth, Túrin will avenge not only himself, but all members of the race of Men.
Morgoth, the first to reign terror upon Middle-earth, was more powerful than Sauron and commanded an army of dragons and Balrogs. While both Morgoth and Sauron were cunning, Morgoth's rule and terror lasted longer and his corruption spread further, making him more formidable in the Lord of the Rings universe.
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.
Sauron seemed to genuinely feel a connection to her, and part of that came from sensing the darkness inside of Galadriel. In that regard, his offer was really a seduction to the dark side.
Thus, Galadriel's dark form in Jackson's The Lord of the Rings personified what would have occurred had the Lady of Lothlorien given in to temptation and taken the One Ring for herself. She would have succumbed to evil because the Ring was indomitable, even with her power.
Wielding the full power of the One Ring would have seemed within Aragorn's abilities to them. Aragorn would have been able to use the Ring more than Frodo could have because Aragorn had a stronger will, one more used to command and authority. Aragorn could have done quite a lot with the Ring.
Elrond didn't want his daughter to die. Her choosing to marry Aragorn meant she chose to die, not to sail into the west with her people. His qualms with Aragorn were more about Arwen's mortality than anything else.
If you were wondering why Aragorn was not a part of "The Hobbit" film, wonder no more. Viggo Mortensen, the actor behind the man who would be king, explains why. And it's pretty simple. Because his character does not appear in the J.R.R. Tolkien novel.
