Legends tell of an invincible martial art known as Mutsu Enmei-Ryu, an unarmed style that allows the user to defeat any number of armed opponents using incredible speed and strength. This is the story of three generations of those who bear the name Mutsu, and their encounters and battles with the strongest fighters of their era.
-taken from AnimeNewsNetwork

Picture	Real Name	Description
	Yakumo Mutsu	Usually pretty calm and laid back, Yakumo also seems to avoid fights whenever possible. He appears in the first arc and is the first mutsu to be featured.
	Miyamoto Musashi	Considered the strongest swordsman of his time, Musashi seeks only to fight the strongest. He becomes interested in Yakumo after first meeting him, he realizes right away how strong he is and seeks to test he skills against that of Yakumo.
	Takato Mutsu	The son of Yakumo, he for the most part seems bored so he decides to follow some travellers he meets when one of them introduces themselves as a Mutsu themselves. In the beginning his identity isn't revealed(but c'mon he looks exactly like Yakumo), he only refers to himself as Yakumo and walks around with one eye closed. He does this because there is no one out there that is strong enough for him to make him use both eyes.
	Jubei Yagyuu	A very strong samurai. It was noted that he exudes the same battle aura as Miyamoto Musashi. His only goal is to find and fight the strongest peole out there.
	Izumi Mutsu	Featured in the last arc, Izumi Mutsu is a later descendent of the first two Mutsu's. He is much more proactive in looking for strong fighters to battle unlike hie descendents. Although gentle and warm hearted he has no problems about killing.
	Ryoma Sakamoto	A strong swordsman who doesnt like to kill, in fact he has never truly awakened his fighting spirit. He had always fought using as little force as he could to defeat his opponents. Upon seeing this Izumi decides to stay by his side until Ryoma is ready to get serious and will fight him with full force.