Anime version
A small feudal lord who wishes to protect her people from a recent rise of banditry. A noble person who loves her white horses.
In Shin Koihime Muso it is revealed that she is a childhood friend of Ryubi Gentoku (the real one), and that she manage to gained possession of the latter's stolen sword before pawning it off to Ensho in exchange for food and support for her people much to her regret (she eventually recognized the sword's scabbard from their time as children). She accompany Ryubi to try to get the sword back from Ensho but despite finding out Ensho no longer has the sword, Ensho decides to cancel Kosonsan debt to her as compensation.
Visual novel version
A feudal lord who initially serves under the En faction before allying herself with the Shu faction. She has a greater role in Shin Koihime Muso.