Jirou

The protagonist of the story, and the son of Tarouza and Oyaruru. He was raised by Tarouza's wife, Tsuyu. After an unknown assailant murdered Tsuyu and her daughter Sayuri, the villagers no longer trusted Jirou and chased him from the village. He then began studying the ways of the ninja under the tutelage of Tenkai. As he grew to adulthood, Jirou gathered pieces to the mystery of the disappearance of his father, and he began to devise a trap to snare Tenkai. In later volumes of the novels, he adopts the name Jirouza Hattori (服部 次郎佐), as well as Gerome Kamui (ジローム・カムイ, Jiroumu Kamui), the name based on that of Geronimo, his adopted father.

(Source: Wikipedia)