There are a lot of great and powerful beings in The Lord of the Rings, but Sauron (the second Dark Lord) is often thought of as the most terrifying, destructive, and powerful being in Middle Earth. He may be the most evil, but is he really the most powerful, or are there other more powerful beings than Sauron that have chosen good over evil?
In The Fellowship of the Ring, Frodo meets the Elven character Galadriel. Viewers who aren't familiar with Tolkien's work have said while watching the film that they were unsure if they could trust Galadriel or not, as she had a suspicious and knowing look in her eyes. Whether it was intentional on the filmmaker's part or not, something about her character seemed a little frightening. During the night, Frodo woke up to find Galadriel wondering about, and he followed her. She allowed him to look into the Mirror of Galadriel which showed Frodo what would happen should he fail his mission.
Frodo—scared and unsure of his abilities—offered the Ring to Galadriel for her to keep safe in a test. In the books, it is said that what is shown next was the image Galadriel presented of herself to Frodo, showing what would happen if she allowed the Ring to corrupt her. Though what she says is different in the book, in the movie she declares, "In place of a Dark Lord, you would have a queen! Not dark, but beautiful and terrible as the dawn! Treacherous as the sea! Stronger than the foundations of the Earth! All shall love me, and despair!" She quickly changed form again back to her fair and good natured image.
After this she says, "I passed the test," meaning she was able to resist the temptation of the Ring and not take it from Frodo, whom she could have easily overpowered. 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. Sauron the deceiver gave three Elves Rings of Power because he knew how strong they were, and he wanted to control them and have them on his side.
Galadriel surpassed all other Elves in beauty, knowledge, and power. Tolkien described her as the mightiest and fairest of all Elves. Galadriel is also one of the oldest beings in Middle Earth, born even before the First Age. Galadriel was a leader in The Rebellion of the Noldor, and left the Undying Lands out of a desire to rule a portion of Middle Earth. It is because of this desire for power that many Tolkien fans say Galadriel would have been more destructive and terrible than Sauron. After all, she did exclaim that she would be "treacherous as the sea" if she were in control of the Ring, which means she too would betray and deceive the Free Peoples of Middle Earth just as easily as Sauron.
Galadriel's power and wisdom were already great, but with the Ring, she would become "stronger than the foundations of the Earth." Her desire to have all beings love her and follow her out of despair and complete loss of hope sounds particularly cruel, even more so than Sauron. In the First Age, Galadriel didn't play any part in the wars. She was offered passage back to Valinor with safe travels, but she did not accept. And in the Second Age, she became the Lady of Lothlórien. During this Age, the fallen Maia Annatar (Sauron, disguised as The Lord of Gifts) convinced Celebrimbor to create the Rings of Power. But Galadriel immediately distrusted Annatar, who was later revealed to be Sauron. This shows how Galadriel was truly wise and all knowing.
Galadriel is actually the Elf who convinced Celebrimbor to hide the Rings of Power, and this is when she was given Nenya—the Ring of Water. Although she never put it on when Sauron still had the One Ring, she did however use it after his defeat to protect the borders of her realm. In the Third Age, Galadriel provided assistance to Eorl the Young, first king of the Rohirrim (not yet formed), in the Battle of the Field of Celebrant against Sauron. It is noted that the Rohirrim regarded both Galadriel and Lothlórien with fear. Perhaps this fear was because the Rohirrim could sense Galadriel's palpable aura of great power.
In The Lord of the Rings, Galadriel chose to use her powers for good, even helping to form the Council of Elrond. Galadriel was not evil. But had she been, there would be none who could stand against her forces, especially if she was in possession of the Ring.