Yujin is one of the younger noble houses of Shi Inkahan. Unlike many noble houses, they do not draw their descent from a hero of the ancient age, but from the House of the Sun itself, through a more modern hero: Xiao Yujin, youngest son of the Emperor Matsuzawa, who was sent west around 2700AC, tasked by his father with protecting the lands of Shi Inkahan from the oni in the Land of Witches. He founded a noble house across the Red Dragon Mountains, on the border between Shi Inkahan and the Land of Witches.
The Yujin family protected Shi Inkahan well until the Fifth Oni Wars in the early 3010s, when they were wiped out almost to a man. The only survivor was Yujin Mikazo, youngest son of the daimyo's youngest brother, who went on to recruit and lead the forces that won the Oni War, and then became Emperor.