Raikō Shimizu is a 20-year-old samurai of the Shimizu clan. His sword is the white gamon, the partner to his sister Raimei's sword. When he was fifteen, he single-handedly massacred his entire clan, with the exception of his sister Raimei. This action is vengeance against his uncle and his gang , who murdered his parents in a coup d'état to take over the clan. After this, he joins the Grey Wolves. He chooses not to tell Raimei his motives behind the massacre to protect her innocence. This leads to a battle between the two. During this battle, his partner Gau is injured trying to stop them and goes comatose. Although Kōga Village's kinjutsushō could have waken Gau up, Raikō refuses to sacrifice the humans needed to use the kinjutsushō. Yoite finally wakes Gau up. Because of this, Raikō feels indebted to Yoite and even disobeys Hattori to allow Yukimi to help Yoite. Eventually, Raikō forfeits his loyalty to the Grey Wolves, particularly Hattori, and is denounced as an expendable pawn and is easily replaced. He helps rescue Miharu from the Grey Wolves. Raikō is portrayed as rather an easygoing person who takes his responsibilities very seriously. It is implied that he is a sadist.
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