Gimli blinked, half raising his hand to shield against the blaze of light and colour, before realising what had happened–that the flash hadn't been the sun caught on glass or steel or even a clear, deep gem– and letting it fall. He squeezed his eyes shut, but that only made the colours reverse, and did not block the light.
"Son?" Glóin asked, pausing at the edge of the balcony, but Gimli shook his head and moved to follow his father. As they took their seats, Gimli swept the room for Khazâd, but saw none. Of course there were none. Here in these Elvish halls what could he hope to find but only Elfkin and a brace of Men? Therefore, he reasoned, he should not be feeling this, or seeing this; it was a Khuzdul matter reserved for his own kind.
And yet one Elf in particular–unfamiliar to him, yet dressed in the green and brown of the woodland folk that neighboured the Lonely Mountain–kept drawing his eyes. At first, Gimli thought he merely sat in a particular shaft of sunlight, which brightened him, but the light fell evenly. The matter was Gimli's own vision, then, taking in the light and colour surrounding the Elf more vividly, until he looked to be enfolded in a rainbow cloak that only Gimli could perceive.
Indeed, the whole company seemed brighter and truer than any Gimli had seen. Not just the company, looking down, the fabric of his own sleeves appeared now to be made of the most lustrous silk, not the care-worn wool of travelling dress. The very air smelled sweeter, he thought, or if not sweeter, than somehow more pure. Thrice, Gimli had battled orc or mountain goblins, and the thrill of battle–where every sense sang and the world moved like cooling slag under the bright whirl of his axe–had not made him feel this alive, this aware.
It was exactly, perfectly, and infuriatingly like the songs said it would be.
Gimli suppressed the urge to sink his head into his hands and weep. He would not shame his father or his people. Not in front of this Elf–this elf who had stolen a thing akin to Gimli's breath, but that surely no Elf or Man could either understand or return. This Elf, who sensed Gimli watching, and held his gaze for the briefest moment–a moment, but long enough for Gimli feel as though his heart had stopped.–before Gimli turned away.
Glóin was looking at him, eyes narrowed.
"Father, who is that?" Gimli asked in a voice too low for even Elf ears to overhear, and pointed with a twitch of his chin.
"Legolas, son of Thranduil of Mirkwood." His father turned away, perhaps assuming that recognising an old rival's kin was what troubled Gimli, or the mere presence of so many Elves about a young Khuzd who had spent most of his years with his own kin. Likely he could not conceive the truth of the matter; such a thing had never happened before, not in all the histories of all the worlds.
Gimli did not correct his father. Instead, he remained silent for the entirety of the council, contemplating what it might mean to at the same moment find one's soulmate and realise that one was utterly damned.