Blood of the Oath (誓いの血 Chikai no Chi) is the 2nd chapter of Nabari no Ou, a manga written and illustrated by Yuhki Kamatani and published in Square Enix's Monthly GFantasy magazine.
Summary[]
After hearing the dangers of possessing and activating the Shinra Banshou, Miharu wishes to remove it. Until this is possible, Tobari asks Miharu to learn ninjutsu and become Nabari's ruler so he can be better protected.