Gothmog, one of the first Balrogs to become Morgoth's allies in the First Age, is regarded as the most powerful Balrog in Middle-earth. As the High Captain of Angband, he is given the title 'Lord of Balrogs'. Although he carries a fiery whip to battle just like the rest, he is also renowned for having a large black ax.
The Elf Ecthelion leads the charge against the Orcs, and fights Gothmog, the greatest Balrog; they wound each other and both fall into the king's fountain in Gondolin; both drown.
Pretty hard to say how much, but given that even a weakened Sauron without the Ring was out of Gandalf the White's power while the balrog was within Gandalf the Grey's power, probably a significant difference.
Gandalf the Grey was able to defeat the Balrog (granted, at the cost of his physical form), so the end result would likely be the same for the significantly more powerful Gandalf the White.
In general Sauron did not seem to be afraid of the Balrog during the Third Age. The behavior of Durin's Bane indicated that he would not leave Moria and its tunnels : he was not a rival for the control of Middle-earth and the Balrog did not share Sauron's abilities as a potential Dark lord.
Gothmog, one of the first Balrogs to become Morgoth's allies in the First Age, is regarded as the most powerful Balrog in Middle-earth. As the High Captain of Angband, he is given the title 'Lord of Balrogs'. Although he carries a fiery whip to battle just like the rest, he is also renowned for having a large black ax.
After sleeping deep within the Misty Mountains for thousands of years, he was awoken by the Dwarves of Moria in the Third Age, responsible for the death of King Durin VI and the ruin of Moria; it was the Balrog encountered by the Fellowship of the Ring.
Still, the dragons proved more effective in battle. Then there's Gandalf the Grey, who managed to kill a Balrog single-handed, but decided to manipulate some Dwarves and one very reluctant hobbit into dealing with Smaug.
So, when Gandalf agreed with Frodo's decision to travel through Moria, he knew that something could be hiding there. Yet, he had no reason to think that it would be something as awful and powerful as a Balrog. Only King Dain Ironfoot knew that Durin's Bane was a Balrog.
Unfortunately, Glorfindel was removed from the Lord of the Rings movies, but one of his most legendary deeds may have been referenced in The Rings of Power season 1. He was the only elf known to go up against a Balrog and win—though the effort cost him his life.
Oh, yes, there are creatures more frightful than Balrogs in Middle Earth. Ungoliant who was able to cry havoc in all Valinor is easily more terrifying than Balrogs, even Morgoth feared its gigantic and hideous form. It took a group of Balrogs and Morgoth himself resisting Ungoliant's attack to make her flee.
Casualties. The Battle of the Peak was the climax of the fight between Gandalf the Grey and the Balrog Durin's Bane atop Zirakzigil after they ascended the Endless Stair from the depths of Moria.
It was said that Morgoth hated and feared the House of Fingolfin most among the Houses of the sons of Finwë, especially Fingolfin's son Turgon, as it was prophesied that his doom would come from the House of Turgon.
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.
There is no account of any dwarf ever killing a Balrog, let alone multiple. The only recorded instances of Balrogs having been slain are Gandalf's slay of Durin's Bane, Echtelion's slay of Gothmog and Glorfindel's slay of an unnamed Balrog.
As the legendarium became more formidable and internally consistent, and the Balrogs more terrible, this number was much reduced. In the end Tolkien stated that there were probably "at most" seven Balrogs: In the margin my father wrote: 'There should not be supposed more than say 3 or at most 7 ever existed. '
After disinheriting his son, King Durin banished Elrond and ordered the new mine to be sealed up, but not before he cast a leaf from the tree in Lindon into the mine, where it floated down and awoke a Balrog that had been lying dormant beneath the mountain.
Sauron's deepest fear was that Aragorn would use the Ring against him. With its powers of domination, Aragorn could comfortably take over the entirety of Sauron's dark army. Though this would eventually corrupt Aragorn, it would allow him to destroy Sauron and take his place.
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.
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.
