Kyōhachirō Hattori (服部 響八郎, Hattori Kyōhachirō) is the nephew and adopted son of Hanzō Hattori the 4th (his birth father was Hanzō Hattori the 2nd). Kyōhachirō was charged by Hanzō to monitor the duel between Kōga and Iga and then report the results to him and Lord Ieyasu. Although he initially has his subordinates witness the battles, following Gennosuke's victory over the Iga at Tsubagakure, Kyōhachirō eventually decides that the Kōga/Iga duel is something he has to see for himself personally. Gradually, Kyōhachirô begins to regret the slaughter caused for the sake of deciding the heir to the shogunate and because of this, Oboro in the anime entrusts him with Gennosuke's flute which she explains is their prayer for the future. After witnessing Oboro and Gennosuke's match alongside his father and realizing just what had been done to them, Kyōhachirō leaves on a pilgrimage to Aekuni Shrine to present Gennosuke's flute as an offering, vowing that even if history forgot the sacrifice made by the twenty ninjas of Kōga and Iga, he would remember them always. In the manga, he doesn't appear until volume 4 when he reports to his father that Lady Ofuku had departed in an attempt to sway victory in the Iga's favor.
Scoping - Kyōhachirō can increase the range of his vision by forming a round formation with is fingers with which he can peek through like a telescope. He uses this to spy over considerable distances.