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, however, was hesitant to take either road. He knew that the Balrog was lurking in Moria, and he also didn't want to face Saruman. So, Gandalf let Frodo decide which road they would take, and Frodo chose the mines, which led to Gandalf's showdown with the Balrog.
In the book, however, he didn't know that the Balrog was there. However, this raises another problem. How did Gandalf not know the Balrog was there? It seems like Gandalf, Saruman or someone on the White Council would have been slightly suspicious after something evil brought a whole Dwarven society to ruin.
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). They very strength and wills were bound to Melkor.
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.
The Dwarves dug too greedily and too deep 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.
Gimli didn't know about Moria's fate because there had been no communication between Erebor and Moria for 25 years, and the Dwarves were hopeful and did not want to accept failure until there was certain news.
What happened to Gandalf after defeating the Balrog?
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.
Gimli and the other Dwarves lived in the kingdom of Erebor and, since Erebor was far away from Moria, news would have been slow between the two kingdoms. The journey to Moria was dangerous, so many messengers could have died going to or from there.
Gandalf didn't know that the Mines of Moria had fallen. He mentions he had been through Moria before, but it was before it had been resettled, which means it would not have had the chance to be overrun yet. All that was known about the mines was that the dwarves had gone silent.
Thrór was murdered as he entered the East-gate of Moria, leading to the War of the Dwarves and Orcs. Even after the end of the War, many Dwarves refused to reclaim Moria, partially because of the Durin's Bane. Years later however, the Dwarves managed to reclaim the Lonely Mountain.
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. '
Who was the elf that fought the Balrog in Lord of the Rings?
Glorfindel fought the Balrog and succeeded in slaying the monster, but was himself mortally wounded. His body was recovered by the great eagle Thorondor and buried under a stone cairn, where afterward grew yellow flowers.
After a brief exchange of blows, Gandalf breaks the bridge beneath the Balrog with his staff. As the Balrog falls, it wraps its whip around Gandalf's legs, dragging him over the edge. Gandalf falls into the abyss, crying "Fly, you fools!". Gandalf and the Balrog fall into a deep lake in Moria's underworld.
Though Gimli has no children, he is not the last Dwarf of Middle-earth. After the fall of Sauron, his people continued to thrive in the Lonely Mountain. Gimli made his home in Rohan, in the Glittering Caves of Aglarond, and many of his kinsfolk came with him.
It is also stated in Unfinished Tales that Gimli was prevented from traveling with his father on the Quest of Erebor because Thorin and Company thought him too young, though Gimli, being in his sixties, considered himself ripe for adventure and was disappointed to be left behind.
Gimli was born in the Ered Luin in the Third Age, son of Glóin. Gimli had wanted to accompany his father on the quest to reclaim Erebor, but at age 62 he was deemed too young. He was a remote descendant of Durin the Deathless, chief of the Seven Fathers of the Dwarves and ancestor of the Longbeards.
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. The Dwarves attempted to fight the Balrog, but its power was far too great for them.
Gandalf's main reason for supporting Thorin's quest in The Hobbit was to eliminate the threat of the dragon Smaug, who would be a powerful ally for Sauron. Despite popular belief, the Balrog known as Durin's Bane was more powerful than Smaug in Middle-earth, being a literal, primordial demon.
When The Fellowship is taken to Galadriel, she and Boromir have a telepathic conversation which immediately causes Boromir to burst into tears. She senses his desires for the Ring but tells him not to give in because even now, there is hope.
Sauron never becomes bound to Middle Earth like Melkor or the Balrogs during the first age because Sauron kept shifting shape, Sauron takes more different forms than any other being in the legendarium. Thus he did not become bound to a single form like Melkor and the Balrogs.
