Melkor is the most powerful of the Valar but he turns to darkness and is renamed Morgoth, the primary antagonist of Arda. All evil in the world of Middle-earth ultimately stems from him. One of the Maiar of Aulë betrays his kind and becomes Morgoth's principal lieutenant and successor, Sauron.
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.
Both Morgoth and Sauron managed to inflict significant damage upon the world and their enemies before their downfall, but Morgoth was undoubtedly the more powerful of the two.
Sauron is known as such, but with a clarification, he is the second Dark Lord. He took over from Morgoth when he fell because Melkor was his teacher and mentor.
Sauron was a servant of Melkor, later known as Morgoth, who is mentioned in 'Rings of Power', basically Lucifer of Middle-earth who brought terrible destruction upon the earth and waged the greatest war against elves.
Sauron is widely known as the main villain of The Lord of the Rings, but before him, Middle-earth was tormented by a more terrible villain, Morgoth.
In The Lord of the Rings, it is said that had Galadriel chosen to use her powers for evil instead of good, she would have been even more destructive and terrifying than Sauron himself. Galadriel was the greatest and most powerful of all Elves in Middle Earth in the Third Age.
God is the most powerful entity in Tolkien's Lord of the Rings universe. The Elvish name for him is actually Eru Ilúvatar, meaning “the one, father of all.” So the question becomes: Who is the second-most powerful being? Originally, it was Melkor, “he who arises in might,” the most powerful of the Ainur (or angels).
Morgoth Was Originally More Powerful Than Sauron
In the depths of time, Eru Ilúvatar created Arda and the Valar. He made the Valar to help create and order the world, but the most powerful Valar, Melkor, turned out to be nothing but problems.
Morgoth's end came in the War of Wrath. The half-elf Eärendil (Elrond's father) led the Valar in the War of Wrath. During this battle, they seized Morgoth and chained him up in Angband. The Valar ejected Morgoth into the Void, an empty place where time did not exist.
Make no mistake, Morgoth is the real enemy of The Lord of the Rings. Despite his seismic importance to Tolkien's lore, Morgoth is never depicted in Peter Jackson's The Lord of the Rings or The Hobbit movies - but Amazon's The Rings of Power finally takes that plunge into darkness.
The Lord of the Rings: The Rings of Power takes place in the Second Age of Middle-earth, when Morgoth, the First Dark Lord, was already defeated.
While the previous 19 rings were crafted with the help of the Elves, the final ring, the 'One Ring to rule them all,' was crafted by Sauron alone; with the ability to dominate the other rings, the One Ring was made with some of Sauron's own power, in order to make it more powerful.
After the downfall of Morgoth, Sauron continually strove to conquer Middle-earth throughout the Second and Third Ages. In the Second Age, under the guise of Annatar, he deceived the Elves of Eregion, who under his guidance had created the Rings of Power, whilst he secretly forged the One Ring in Mount Doom.
Peter Jackson certainly makes the assertion in the theatrical and extended editions of the Hobbit movies that Smaug and Sauron are not only well aware of each other, but are planning to ally with each other. Smaug even seems to have detailed knowledge of Sauron's coming plans.
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.
Eru is introduced in The Silmarillion as the supreme being of the universe, creator of all existence, including the world, Arda, and its central continent, Middle-earth. In Tolkien's invented Elvish language Quenya, Eru means "The One", or "He that is Alone" and Ilúvatar signifies "Allfather".
After Melkor's defeat in the First Age, Sauron becomes the second Dark Lord and creates the Rings of Power to suppress and conquer Arda.
Sauron feared her
The author said that she was the “last remaining of the Great among the High Elves” in the Third Age, and consequently was the one person Sauron must have feared most among all his enemies in the War of the Ring.
She already feels an outcast after Gil-galad tried to send her back to the Undying Lands, and she fears that if she reveals what she has done, it will be the final nail in the coffin. Instead, when Elrond pulls her from the river Glanduin, and she races back inside to Celebrimbor's forge, she chooses to stay silent.
All other men in the trilogy, even the underestimated and underappreciated Faramir, and his mighty brother Boromir, fall short of Aragorn's heroism. That is why Aragorn is the only one who could challenge Sauron in the Palantir, and win. In the film version, Gandalf confides in Aragorn “The rumor has reached him.
Isildur took up the hilt-shard of Narsil and cut the One Ring from Sauron's hand, vanquishing Sauron.
The death of the white wizard Saruman differs slightly from Tolkien's original book Return of the King to Peter Jackson's film adaptation of the same name. But although the whereabouts and the circumstances change between the two, both versions agree that Saruman is killed by Grima Wormtongue.
Gandalf's spirit is there called the 'fire that kindles' in direct opposition to Sauron, the 'fire that devours and wastes'. It's clear from this that Gandalf had a particular role as Sauron's direct opposite, even among those of his own order.