The Blood Betrayal was an event in YiTish myth that ushered in the Long Night and the subsequent fall of the Great Empire of the Dawn.
The Opal Emperor was the seventh ruler of a line that began with the God-on-Earth, the son of the Maiden-Made-of-Light and the Lion of Night. He was succeeded by his daughter, the Amethyst Empress, but her younger brother, envious, cast her down and slew her, taking the crown and proclaiming himself the Bloodstone Emperor. He turned his back on the gods of Yi Ti and began worshiping a black stone that had fallen from the skies, took a tiger-woman as wife, practiced cannibalism and necromancy, and enslaved his own people. Horrified at the Blood Betrayal, the Maiden-Made-of-Light turned her back upon the world and the Lion of Night came forth in all his fury to punish the wickedness of man.
- ↑ 1.0 1.1 The World of Ice & Fire, Yi Ti.