He was a descendant of Durin the Deathless, father of the first house of the Dwarven people. Gimli was descended from, but was not a member of the royal line. Through his father, Gimli was also the first cousin once removed of Balin, Lord of Moria, and his brother Dwalin, two more former companions of Bilbo.
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.
He was a remote descendant of Durin the Deathless, chief of the Seven Fathers of the Dwarves and ancestor of the Longbeards. Gimli was of the royal line, but not close to the succession; he was the third cousin once removed of Dáin II Ironfoot.
Gimli: [chanting softly, sobbing] "Kilmin malur ni zaram kalil ra narag. Kheled-zâram… Balin tazlifi." Legolas: [to Aragorn] "We must move on, we cannot linger!"
The Hobbit - The Desolation of Smaug - ''That's my wee lad Gimli''
Why did Gimli not know Balin was dead?
Unfortunately, the Fellowship's journey only confirmed what he had feared. Although Gimli knew that Moria could be dangerous in the book, he did not know about Balin's death in The Lord of the Rings: The Fellowship of the Ring movie possibly due to slow communication and Dwarves' perception of time.
Boromir was put under great stress by his father to retrieve the Ring, and he let the Ring take control of his mind. Because of this, he is ashamed and disappointed in himself. This proves the Boromir is at his core a good person. Boromir knows what he has been thinking is wrong, and so he cries.
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.
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.
Thorin I (Third Age 2035 – 2289, died aged 254) was the King of Durin's Folk for 99 years, succeeding his father, Thráin I, on his death in T.A. 2190. Thorin was the heir of Durin the Deathless being the great-grandson of Durin VI.
But on 10 November T.A. 2994, as Balin went to look in Mirrormere, an orc archer fatally shot him. Balin's body was placed in a tomb in the Chamber of Mazarbul. But the archer was just the van of the orcs who came up the Silverlode. The Dwarves were trapped.
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.
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's occasionally mean attitude towards Pippin is rooted in factors such as the stakes of their mission, Gandalf's protective instincts towards hobbits, and his desire to mentor Pippin, offer him guidance, and see him grow.
Simply put, he was the only one available. There were only two dwarves at the council of Elrond, Gimli and his father Gloin. The Dwarves were fighting Sauron's forces constantly in their own campaign and couldn't spare many. Gloin was also much older now, it was absolutely his son's turn to go on a big journey.
Sometime afterward in the coming years before his expedition in TA 2989, Balin would visit Bilbo at least one more time. During this visit to the Shire, Balin met Bilbo's newly adopted heir of Bag End, Frodo, and the young Hobbit would come to learn of some of Balin and his Uncle's travels to the lonely mountain.
Well, we don't really know how old Legolas is, not in canon. But certainly he is much older than Gimli. But to a dwarf's eyes (and to be fair, our own) he looks younger. And in terms of lifespan, Gimli has lived far more of his own life than Legolas has of his own.
As far as mortality, no. Mortals don't gain immortality in Valinor. In fact, being there speeds up their deaths, which is one of the reasons mortals are banned from entering.
From TA 2989 to TA 2994, the re-colonization of Moria was an attempted expedition led by Balin to re-take the ancient Dwarven Kingdom of Khazad-dûm. An initial effort was successful in reclaiming some of Moria from the Orcs.
Legolas and Gimli's relationship is strong in The Lord of the Rings, even though it wasn't explicitly romantic in Tolkien's source material. The members of the Fellowship in The Lord of the Rings forge an unbreakable bond while on their mission to destroy the One Ring.
Gimli is not the last of the dwarves. This is a common misconception because Gimli is the only dwarf who gets a fair amount of coverage in the franchise. Lord of the Rings focuses its narrative primarily on the affairs of men, elves, and hobbits. Dwarves are a secluded race that lives in the mountains.
Despite her suspicions of Boromir and the massive rift between the races of Middle-earth, Galadriel understood that uniting all people was the only way they could defeat Sauron. The small act of passing her gift on to Boromir was a step in the right direction that the films failed to elaborate on.
It was as if the Ring had granted him a vision of what could happen if the great Elf were to wield its power. Jackson, on the other hand, used Galadriel's dark form as a visual cue for the audience. Specifically, it represented how she would become evil if she gave in to her deepest desire.
When Galadriel tells Frodo, “To bear a ring of power is to be alone,” she demonstrates her understanding of exactly how enormous Frodo's task is, and how separate he is from the rest of the fellowship. His task is completely solitary, and it will consume his life.
