The key character of the side story. A mysterious man with the same name as the legendary hero of So (楚), a country that perished 400 years ago.
He possesses the prowess to drive back an army by himself and will never serve under anyone. He blows his whistle as he wanders Mirisha.
His covered right arm holds a mysterious power, a power that is even hidden from himself.
He seems to be from Kishuu, the stage of the Red Cliff battle.