However, in the Tolkien novel, Gandalf actually never knew about the Balrog. All he knew was that
Therefore, the only explanation as to why Gandalf doesn't reveal the Balrog's presence to the others earlier in the films, is that it is a plot device used by the writers and the creative team in order to increase the dramatic tension of Frodo's decision.
Gandalf was scared of this beast because he knew how powerful it was since it was a Maia like himself, but it was purely evil.
Why didn't he? He had been through Moria (more than once), but if memory serves he had only gone East to West, never West to East. So when he came to this place before, he may not have realized it was a fork in the road as he was coming out if the fork, not into the fork.
Answer and Explanation: Yes, Sauron knew about the balrog in Moria, as did Saruman, Sauron's lieutenant. However, Sauron did not attempt to recruit the Balrog to his side. The Balrog is a supernatural being who is on a similar level with Sauron.
In January of 3019, the Fellowship of the Ring travelled through Moria on the way to Mount Doom. There they encountered Durin's Bane at the Bridge of Khazad-dûm. The Elf Legolas instantly recognised the Balrog despite having never seen one before.
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. '
Gandalf was himself utterly spent in the battle, and after the fall of the Balrog, he too collapsed into darkness and died. For nineteen days Gandalf's body lay on the mountain, until his spirit was sent back to complete his mission in Middle-earth, and thus he returned to life as Gandalf the White.
Gandalf wasn't in Middle Earth at the time. The Battle of the Last Alliance took place at the end of the Second Age, and the arrival of the Ishtari (Wizards) from Valinor took place at around the year 1000 of the Third Age.
Gimli, the dwarf, did not know that Moria had fallen because he was not present during the events that led to its fall.
So, one glimpse into Smaug's eyes and the Balrog falls under the spell. Even if it's just for a second—a moment of hesitation or distraction, it'd be enough. Smaug would snatch up Durin's Bane and gobble him up with his sword-sharp teeth (and we know swords can kill Balrogs).
No, Balrogs do not serve Sauron. Similar to Sauron, Balrogs are Maiar, powerful spiritual beings second only to the Valar themselves. They were corrupted by Melkor's evil before the first age and were made into Valaraukar (Demons of Power).
The Balrog killed Durin VI, the Dwarf-King of Khazad-dûm, whereafter it was called Durin's Bane by the Dwarves. Avarice, principally for mithril, drove the dwarves to go too deep and awaken the Balrog.
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.
Thus, Sauron wasn't in Morgoth's service when the Balrogs chained themselves to a terrestrial form. That's why Sauron didn't look the same as a Balrog -- because he was still free to take on whatever form he wanted.
I think Aragorn was as unfamiliar with the western side of Moria's tunnels as everyone else but Gandalf. He was also unaware of the presence of the Balrog (for he surely would have said something had he known such a monster was there). And he knew nothing of the fate of Balin's colony.
Over the next 17 years, Gandalf travels extensively, searching for answers on the ring. He finds some answers in Isildur's scroll, in the archives of Minas Tirith. Gandalf searches long and hard for Gollum, often assisted by Aragorn, who eventually succeeds in capturing Gollum.
According to Tolkien's writing, Galadriel didn't fight in the War of Wrath because she didn't believe Morgoth could be defeated without the help of the Valar.
Most characters in The Lord of the Rings got to work rebuilding what was lost, but Galadriel decided to rest. She had begun her war against Sauron halfway through the Second Age, meaning that by the time Sauron was defeated, she had been in the fight for over 3000 years.
The Dwarves dug too deep, greedy for mithril, and disturbed a demon of great power: a Balrog, which destroyed their kingdom. By the end of the Third Age, Moria had long been abandoned by the Dwarves, and was a place of evil repute.
Nevertheless everything went well as the Dwarves were fiercely determined to take back their home, slaying every goblin in their path, eventually some of Moria was reclaimed and they dwelt in the Twenty-first Hall until Balin moved to the Chamber of Mazarbul, which then became his seat of rule.
No. In the book, Gandalf specifically tells Aragorn, Boromir and Legolas that the Balrog was a foe beyond any of them. He knew it might be beyond even his powers to deal with, and there was nothing an elf and two men could bring to the fight that he couldn't.
Lord of Balrogs
The most powerful of all the Balrogs, one of the chief servants of Melkor, who held an authority hardly less than Sauron himself. A wily commander and fearsome fighter, Gothmog was often accompanied by others of his fiery kind, and at least in the Nirnaeth he had a personal guard of dozens of Trolls.
Gothmog (Sindarin IPA: [ˈɡoθmoɡ]) was the first Lord of Balrogs during the First Age, and the greatest Balrog ever to walk Middle-earth. He held the title of High-captain of Angband, being Morgoth's front-line lieutenant as well as one of his most important servants.
So, in terms of "angelic rankings," they were on the same level, which meant that Sauron had no authority to commander the Balrog. As a Valar, Morgoth led a whole slew of Balrogs in the First Age, but because Sauron was only a Maia, the Balrog would have had no loyalty to him.