Nabari No Ou Series by Yuhki Kamatani, Vuhki Kamatani

Apathetic schoolboy Miharu Rokujou is content to meander through life in the sleepy village of Banten. But his quiet existence is shattered when the Grey Wolves of Iga, a powerful ninja clan, attempt to kidnap him in broad daylight. Only then does Miharu discover that the ultimate power of the hidden ninja realm — a power that can do both great good and great harm — is sealed within his body... moreApathetic schoolboy Miharu Rokujou is content to meander through life in the sleepy village of Banten. But his quiet existence is shattered when the Grey Wolves of Iga, a powerful ninja clan, attempt to kidnap him in broad daylight. Only then does Miharu discover that the ultimate power of the hidden ninja realm — a power that can do both great good and great harm — is sealed within his body. As battles erupt among rival ninja clans seeking to control him, Miharu must overcome his apathy and learn the ways of the ninja if he wants any shot at survival! less

Who is friend, and who is foe? Kouichi and Shijima once fought alongside Raimei and Banten, but now they cannot see eye to eye with the revived Shimizu clan, whose top priority is the nullification of the secret art... moreWho is friend, and who is foe? Kouichi and Shijima once fought alongside Raimei and Banten, but now they cannot see eye to eye with the revived Shimizu clan, whose top priority is the nullification of the secret art. Is it the unavoidable destiny of two old friends to take up arms against each other? As the lines of alliance blur with conflict, the story of the Shinra Banshou reels wildly on, with Kotarou Fuuma, the Nabari realm's biggest power player, smiling to himself knowingly, while pulling all the strings... less