Originally born in Ireland, a teen Tobari Kumohira was dragged "kicking and screaming" onto a plane by his
Grandfather, a "Japan otaku" and "ninja fanatic", to travel to Japan and learn to become a ninja. There Tobari and his Grandfather became close to the Rokujou famiy. Which led to his involvement with the Shinra Banshou user's death, Asahi Rokujou, Miharu's mother. The Kairoshu had come for the Shinra Banshou. Running for their lives within the forest, Asahi's husband grew too tired to continue on so Tobari's Grandfather choose to stay behind with him as Tobari, Asahi, and a young Miharu escaped. In place of Asahi, Tobari soon turned back for the others, telling Asahi to get herself and Miharu to the village of the Fuuma. Arriving too late, Tobari found his Grandfather and Asahi's husband already killed by the pursuing ninjas. He rushed back to Asahi who had been attacked by the ninjas, too late to save her, Asahi slowly died. As the Shinra Banshou left her body and went within Miharu's she told her son to forget all that had happened. Everyone had lost their memories, including Miharu, and had forgotten that Miharu was now the bearer of the Shinra Banshou, all excepted Tobari. Asahi had told him that he must be the only one who remembered.
10 years later, Tobari now works as a teacher in the same school Miharu, who had forgotten of Tobari's relationship with his family, attends. Tobari tries to explain to Miharu that their are ninja's after him, but Rokujou is not convinced and does not take his warnings seriously. Soon after, Miharu is targeted by ninjas who want to take a hijutsu from him. Durring the chaos, the Shinra Banshou is awakened within Miharu and he becomes possessed by it. After Kouichi's failed attempted to seal it, Tobair steps in and knocks Miharu out, repressing the Shinra Banshou for the time being.
When Miharu wakes up in the school hospital he asked Tobari to remove the Shinra Banshou from him. But
Kumohira explains that if it could be done, it would have been done already. Tobari then tells Miharu that he must become the ruler of Nabari and kneels before him, pledging his life and honor to Miharu.
Not long after, as Miharu had agreed to work with Tobari and Kouichi, Raimei shows up. A young samurai girl who Tobari knew from before. She said she had come to test the owner of the Shinra Banshou and wants to take Miharu to the Fuuma village. Tobari is reluctent to let Miharu go but ends up at the train station with Miharu, Kouichi, and Raimei. They disguise their trip as a fieldtrip but as the three students bored the bullet train, they see Tobari outside their widow waving and telling them to keep save. Agreeing at first, they finally realize and Raimei points out that Tobari was suppose to be coming with them. Thus, leaing to their discovering of Tobari's strong hatred of transports due to his amaxophobia (a fear for riding or being in vehicles). They asked him how he was able to get to Tokyo then and he replies "I walked."
One unpleasent train ride later, they arrive at the Fuuma village to find two Grey Wolves there to seal the
village's forbidden secret scroll. Tobari and his students fight to get the scroll back, but when the Grey Wolf's Kira user, Yoite, gets involved it is all they can do to survive. While Kouichi and Raimei are taken down, Tobari is face-to-face with Yoite, trying to block the Kira with his unseal technique and protect Miharu. On the verge of complete defeat, the village's leader, Kotarou Fuuma, shows up just in time to save them.
Wounded from the encounter with the Kira user Yoite, Tobari wakes up in the care of the Fuuma village. Miharu silently sitting on the floor beside his bed, Tobari is relieved to find him okay. Though when Miharu tells Tobari about being picked on by Kotarou, Kumohira, despite his still recovering wounds, is later seen up and yelling at the Fuuma leader, nearly injuring himself further. Miharu and Raimei watch as Tobari strains himself to the point of passing over and Raimei looks to Miharu saying that he really should stop messing with Tobari Sensei.
Now with the aid of the Fuuma, Tobari, Miharu, Kouichi, and Raimei all work to find a way to harmlessly strip the Shinra Banshou from Miharu. However, Miharu is then kidnapped by Yoite who left no sign of where he had taken him. Tobari is of course frantic until the next day when he finds Miharu simply working in his grandmother's restaruant as if nothing had happened. After an overly dramatic response, Tobari demands to know what had happened, but Miharu is reluctant and does not tell Tobari, causing a tension between the two.