|Japanese name:||服部 響八郎, Hattori Kyōhachirō|
|Occupation:||Member of the Tokugawa Shogunate|
|Family:||Masanari (Grandfather); Masanari II (Father); Masahiro (Uncle/Adopted Father)|
|Manga Debut:||Chapter 26|
|Anime Debut:||Episode 5|
Kyohachiro Hattori (服部 響八郎, Hattori Kyōhachirō) is the nephew and adopted son of Hattori Hanzo the 4th (his birth father was Hattori Hanzo the 2nd). Kyohachiro was charged by Hanzo to monitor the duel between Kouga 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, Kyohachiro eventually decides that the Kouga/Iga duel is something he has to see for himself personally. Gradually, Kyohachiro 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, Kyohachiro 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 Kouga 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.