The Eye of Nechemyyeh
The Eye of Nechemyyeh is a story written by Tsukizubon Saruko and illustrated by neomeruru. It ran in Issue 39 at http://s2b2.livejournal.com/223039.html, and is mirrored at http://www.shousetsubangbang.com/mirror/the-eye-of-nechemyyeh/.
From isis.dreamwidth.org: "In a sort of Biblical-feeling world, twins are reserved for the gods: the older will be a prophet, and the younger ceremonially sacrificed upon coming of age."
From fail-fandomanon.dreamwidth.org: "Kebineh and his twin Regi have been promised to the temple since they were children; and as he grows up Kebineh is drawn to the priest Chakred. Includes dub/noncon, underage, major character death, and an unhappy ending."
Their parents had given them up to the temple together, as soon as they were both old enough to wean from their mother's breast. It was the first and only home either of them had ever known. Kebineh's earliest, foggiest memory was an image of the sky pitching forward and toppling away, as his back struck the paving-stones of the steps inside from the courtyard; he remembered wailing, and then the face of a priest looming into his vision, all stretched around a round concerned O of a mouth. He had been lucky, he had been admonished many times since, long after he could no longer remember why he'd thought it was a good idea to run up the steps as fast as his chubby toddler's legs could go. Lucky, to have come away with only bruises and a bump on the head. Of course, what the priests really meant (Regidhu had whispered, mischievously, in their bed in the dark) was that they had been lucky. He was their highest duty, after all, not the other way around.