She/Her– Isoldine was a paladin of the Avriel, the winged elves of Samsarras. When the first war happened, she slew many of the Caelen family, leading legions in the sky. She was said to make it rain blood with her glass sword, showering the plants below with scarlet droplets from her slain foes.
It was after the war that the problems arose. The losers of the first war were cast down to the earth, their wings amputated from their backs. Isoldine was not sated, however. She would fly to the earth, finding her disgraced brethren, and kill them in whatever numbers she could. It was not long before she bloodied her hands with the life of her own kin, killing those that were still avriel. She used the justification that they were not pure enough, not worthy of their wings.
She was eventually captured, though it cost avriel lives to do so. The Council amputated her wings, just as they did with the high elves. Due to the gravity of her crimes, however, they did not allow her to land safely on land first. She was thrown from one of their cloud cities in the sky so that she may plummet to her death, as it was judged that letting her live would be too risky.
She did not die, however. Her want of vengeance kept her alive and it still does to this day. She rides a skeletal horse through the elf lands, awakening every few decades to kill again as a Death Knight. Many believe this to be just a legend. There are not many left alive that can espouse otherwise.