O-Parts Hunter volume 1 features story and art by Seishi Kishimoto.

In the not-to-distant future, mankind fights over O-Parts, relics from an ancient civilization, each of which contains incredible powers. Some people with special abilities are able to use the O-Parts to their full potential, and are known as O.P.T.s (or O-Parts Tacticians). Naturally, O-Parts can be used for both good and evil purposes.

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 actually a very powerful O.P.T, and inside him sleeps a demon of incredible ferocity. He meets up with a girl named Ruby who wants to become a treasure hunter like her famous father before her.

Though Jio doesn't believe in friendship, he agrees to be Ruby's bodyguard, and together they go on a dangerous quest to discover as many O-Parts as they can.