Qwan / 怪・力・乱・神クワン Series by Aki Shimizu

In the mystical lands of ancient China, where magical beings are a part of everyday life, Qwan is a strange boy who can devour demons and absorb their power. However, he's looking for more than a quick bite. Qwan's quest is to find the sutra known as the Essential Arts of Peace, which will ultimately reveal the purpose and truth to his existence!

The search for the Essential Arts of Peace is a dangerous and deadly affair. Betrayal upon betrayal surrounds Qwan; Daki, sent by Yuushi to stop Qwan, has agreed to lead him to the sutra. Yuushi, who also wants the sutra, is furious and drives Daki's mother to ambush Qwan! Can Qwan get to the Essential Arts of Peace in time?

In the world of the immortals, just as he discovers that his purpose is the cleansing of people from Earth, Qwan has his powers stolen away from him. Ukitsu manages to save Qwans life and send Shaga and him back to Earth, however Ukitsus own fate is uncertain. Older teens.