question:  What is special about light in this story?
context: But its outward perils could not compare with the Ryzgas themselves, who slept within, ready to wake and conquer.... The ice-wind blew from the glacier, but Var's love was round her as a warming cloak, a cloak that glowed softly golden in the deepening twilight, even as her love was about him. For the flame that had sprung between them at the Truce of New Grass, she had challenged the feud of their peoples and had left her home, to follow him. While she waited he spun a dream, attaching it to the crags that loomed over the pass, and to the frozen ground underfoot. It was starry night already when they saw the light from the Watcher's cave. Var saw with some surprise that all the walls were sheathed in ice—warm to the touch, bound fast against melting by the Watcher's will. Behind them began a tinkling of falling water, thawed from the glacial ridges above to descend sheet-wise over the cave mouth, freezing as it fell into lengthening icicles. Hot food and drink were before them almost at once. Warming to the old man now, Var sketched his and Neena's history briefly. When I had gone that far, the mountain began to shake, the force that is in the Earth rumbled below, and I returned in time." "But they were such a race as the world has not seen before or since. They were great and evil as no other people has been, because they wanted the stars. "Because of them we must build with dreams instead of iron, and our only fire is that of the Sun, and even now, two thousand years later, the Earth is still slowly recovering from the pangs and poison of that age. And we—we too are a remnant, the descendants of the few out of all humanity that survived when the Ryzgas' world went down in flame and thunder.
output:  It can be manipulated by the people
options:  It is traded like a commodity  It is the only way the adventurers nowhere to go  It can be manipulated by the people  It is liquid-like in its composition