Legend of the Five Rings - The Way of Bushido
The Obsidian Dragon despised Hitomi, Lady Moon. In 1170, the Dragons, tired of Man’s rule of the Heavens, exerted their will upon Tengoku. The Seven Fortunes allowed the Dragon of Jade and the Dragon of Obsidian to replace Hida Yakamo as Lord Sun and Hitomi as Lord Moon respectively. The other Dragons, save the Dragon of Thunder, left mankind to cement their power.
In 1170 the Obsidian Dragon was successful in defeating Hitomi, becoming the next Lord Moon.