Kotarou Fuuma
The leader of Fūma village, who has written almost all the texts regarding ninjutsu and the Shinrabanshō. He knows all about the world of Nabari and ninja techniques, with the exception of the kinjutsus of other villages. He loves women, as most of the residents of his village are female, and he claims that if he had the power of the Shinrabanshō, he would turn the Fūma village into a paradise where all the women of the world are in love with him. However, according to Raimei, he is lying ninety percent of the time. He has spies hidden within the other ninja villages. According to him, he was born on December 31 at exactly 23:59.
It’s revealed in chapter 69 of the manga that Fuuma was a human born 114 years ago in the Edo period; he couldn’t accept dying without being able to touch the wisdom of the Shinrabanshou. By acquiring Fuuma’s hidden jutsu Tenpenka and Iga’s forbidden jutsu Kira, he can take the form of a young Fuuma Kotarou and the Kira-using leader of Kairoshuu’s secret intelligence unit, Inasa. 10 years ago, it was him who killed Miharu and forced Asahi to activate the Shinrabanshou to revive Miharu.
Fuuma’s wish is to acquire the Shinrabanshou for himself, and meet its female spirit, whome he affectionately calls “Shinra”. In chapter 70, he almost successfully extracts the Shinrabanshou from Miharu, but Thobari stabbed him in the neck, killing him. Unable to withstand the jutsu, Fuuma’s body breaks down, and rots to the bone.