Main hero raised in a public bathhouse in Nagasaki. He can't control his fiery energy to become the strongest man, and spends his days taking on fights. He has dominated Nagasaki, but is not satisfied. There is a certain reason for which he breaks out in hives when he touches women, and that is why he is still a virgin. However, he does not know that being a virgin has great meaning to him.

Female ninja from Iga. She was raised with strict discipline as a ninja to carry out missions with loyalty and in cold blood. For hits reason, she lacks human emotions such as sympathizing with others. Her actions place highest priority on the Tokugawa Shogun family and the mission, which leads to many conflicts with Keiichiro.

She looks like a sweet little girl, but is actually half fox demon and half human. Her bushy tail is always sticking out from behind. She is a tomboy with and unyielding spirit, but has long lived as a social outcast because she is half demon. She meets Keiichiro and starts to change as she develops an affection for him.

Keiichiro's “sworn brother” who adores him unconditionally and is always accompanying him. He's not a fighter at all, but is fanatical about foreign countries and machinery and has invented many new machines. Physically weak, but tries desperately to support Keiichiro. He is proud of his slicked topknot hairstyle.

A voluptuous and beautiful “mystery woman.” She talks like an Oiran (courtesan), and everything she says is erotic. She confronts Keiichiro and Kiriko several times for a particular purpose. Master of kung fu and uses a giant iron fan.