A man covered in scars known as the "Killer of 99", Shungiku is a convict murderer who joins Mushibugyō in an act of repentance. The son of a bandit, he tried to avoid a life of crime until his mother is murdered, and blaming his father for it, he slays his gang and everyone else in his way in a killing frenzy that ends with his father's death, just to later know that she died by the hands of a member of Mushikari. Since then he looks for the man responsible for her death to avenge her.

Spoiler

After finally avenging his mother, Shungiku changes his title to "Killer of 100".