Rokujo's and Kouichi's 25-year-old english teacher in the "front world".
Born in Ireland on March 17, Kumohira is actually a ninja of the Banten village in the world of Nabari. He is entirely devoted to protecting Rokujo, and wants him to become the ruler of Nabari. He has an intense hatred of transport, such as trains and buses, and would not get on one until Miharu manages to "persuade" him. He went to Japan because his grandfather was a "Japan otaku" and "ninja fanatic", who forced him to go to learn to become a ninja, and was unable to return home for ten years (partly due to his phobia of vehicles). It was during this time that he became the Rokujo family's close acquaintance, the memories about which Miharu has lost after an incident concerning the Shinrabanshou and its user (who was either Miharu's father, Akatsuki Rokujo, or his mother, Asahi Rokujo) killed his parents and Kumohira's grandfather and erased the concerned individuals' memories about it, except Kumohira's himself, 10 years ago. In the anime, he is the temporary leader as the current leader is away, while in the manga, he is not just a stand-in, but actually has the power to arrange for a temporary leader. According to Aizawa, Kumohira has probably recorded Banten's kinjutsu through verbal communication.