Legend of the Five Rings - The Way of Bushido
Fu Leng, also called the Ninth Kami and the Dark Kami, was the lost brother of the eight Kami who fell into Ningen-do, the Realm of Mortals, and founded the Empire of Rokugan, but his true name was lost to time. It was Fu Leng who initially caused the fall of the Kami from the Celestial Heavens, and Fu Leng who fell past Ningen-do and into Jigoku, the Realm of Evil. Corrupted by the malign influence of Jigoku but still possessed of the divinity that his siblings had lost when they fell into the Mortal Realm, Fu Leng attempted multiple times to conquer and destroy the Emerald Empire that his siblings built. This desire for conquest was driven by his misguided and deeply vengeful belief that his siblings had intentionally allowed him to remain trapped in Jigoku after he had fallen from the Heavens. Amongst the Kami he was regarded as the second-best at nearly everything, excluding patience and bravery.
Like his brother the Kami Togashi, founder of the Dragon Clan, Fu Leng was able to take on the form of a dragon.