Yotsu Yatoshin

In 1111, the ronin Yotsu saved the life of the son of Hantei XXXVIII, Hantei Sotorii. In gratitude, the Emperor gave Yotsu the name Yotsu Yatoshin, the Emperor's father's name, and allowed Yostsu to let his family take his name. The Yotsu are still ronin, but they are a family recognized by the Emperor, nonetheless.

Sword of Yotsu
In 1116, Yatsu Yatoshin formed the Sword of Yotsu otokodate and began granting fealty to any ronin who wanted to learn the techniques the old ronin developed while living in the mountains.