O-Parts Hunter Vol. 1 (manga)

Jio is a young boy with a tragic past who only trusts one thing in the world: money. Little does he suspect that he is also a very powerful O.P.T., and inside him sleeps a demon of incredible ferocity. He meets up with a girl named Ruby, and together they decide to embark on a dangerous quest to discover as many O-Parts as they can. Will Jio help Ruby realize her dream of becoming a world famous treasure hunter? More importantly, will Ruby help Jio realize his dream--of world domination?!