The children of Elrond are interesting, in that they all appear on-page, but tell us next to nothing about themselves.
Elladan and Elrohir were born in 130 T.A., their sister Arwen some hundred years later - which, by the time of the War of the Ring, makes them essentially the same age. By the year 350, they would all have been well into adulthood. They would have known that they had a Choice to make, the choice between elven immortality and the Gift of Men - but they also knew that it was far into their future.
Still, it's hard to imagine they wouldn't have thought about it occasionally, and watched the events around them with a judging eye, trying to determine which life was 'better'. They would have seen, and visited, the fading remnants of the elven kingdoms - Lindon and Mithlond, Lorien and Greenwood - and would have watched the Kingdoms of Men grow into their full glory.
But then, on the flipside, they would have seen the dissolution of Arnor, and the northern Dunedain falling into civil war. They would all have witnessed the rise of Angmar - and this is where they actually step into history, for we know that the Eldar actually fought in some of those wars. Were the children of Elrond among them? Elladan, Elrohir - and even Arwen, because the Eldar didn't believe that 'women can't fight'.
Whether they took part in the wars or not, it must have made them distinctly dubious about the mortal side of their ancestry. With all the infighting, the shattered North Kingdom was a showcase of the worst men had to offer - and in the end, it was betrayal and indifference by the South Kingdom of Gondor that led to Arthedain's final ruin.
But then the coin flips the other way. A darkness awakens in Moria - and rather than helping to fight it, or the orcs which follow, Amroth of Lorien shuns the dwarves. Galadriel and Celeborn, still living in Lorien, go along with this - if, indeed, it wasn't Galadriel's suggestion, her foresight showing her a hint of what the dwarves had uncovered. Then, too, came the great shock of Amroth's death, drowning while trying to cross the Sea - a reminder that even for the Eldar, the passage West was not a foregone conclusion.
And in 2012 T.A., a small boy was brought to their house: a cousin of theirs, Elrond would have told them, though far removed in generation. Arahael, and all the little boys who followed him, showed Elrond's children what mortal men were truly like: the innocence, the honour, the glory, and, yes, the corruption, the wickedness, the thoughtlessness. It's hard to imagine Elrond didn't know what he was doing: showing his children both sides of their choice, not hiding anything, trusting them to make their own decisions.
Then comes the great shift: Celebrian is attacked, and departs for Valinor. Arwen, whether she used to be a warrior or a healer, actually seems to suffer from depression after this - she turns inwards, to the point where her sewing a banner for Aragorn is viewed as a great achievement. We know she spent time in Lorien, on Cerin Amroth - the memorial to their lost king, and in her mind, to her departed mother. Perhaps she found some peace in the timelessness of the Golden Wood.
And then came Aragorn - one of the endless stream of little boys, now grown up, a cousin become a vision out of the past. What did Arwen see in him, that made her fall so deeply in love with him - that drew her out of herself and let her help and support him? Well, she was in Lothlorien at the time... did she look into the Mirror? Perhaps.
But what about her brothers? They, too, became obsessive after Celebrian's departure - but their obsession was with hunting and killing orcs. They rode with the Dunedain on their hunts - they took those little boys and followed them into battle, defending the lands around so that no-one else would have to suffer as they did.
We all know their story in the War of the Ring, I won't repeat it here - but what about after? Arwen, of course, married Aragorn and later died, but her brothers? Tolkien remains silent on whether they sailed at last to Valinor, or stayed behind to become mortal.
To find out, let's go right back - back to their names. Names are often significant to the Eldar, and these weren't just any children - they were the sons and daughters of Galadriel's child, a child who may well have shared her mother's gift of foresight.
Arwen Undomiel is the only one known to have two names - and the first, interestingly, has the same meaning as her grandmother's. Ar-wen, 'Noble Maiden', is not so different from Galadriel's father-name, 'Artanis', 'Noble Woman'. And the second?
The Evenstar is Eärendil, Arwen's grandfather (Elrond's father). So already she is named for her two greatest grandparents - but the Evenstar name has more significance than that. Lingering in the West after the sun sets, it is a guide to the Eldar, leading them along the Straight Road - and when it fades, night has truly come.
The name is prophetic, in more ways than one. So... could the twins' names be, too? The Elf-Rider Elrohir, and the Elf-Man Elladan: might it be that Elrohir was foreseen to become a brave knight in the war with Angmar, and ultimately to choose to be an elf, while Elladan, moved by the plight of mortals, elected to join them? If so, it would be a mirror to their father's life: his own twin brother, Elros, became a mortal king, while Elrond became a powerful Elf Lord.
But like all things elven, this mirror had faded by the Fourth Age. There were no kingships or lordships remaining: just the Straight Road into the West, or life in the Last Homely House as the Reunited Kingdom grew bright and glorious - without the Eldar.