Friends

The Dream 1

The Dream 2

The Five Rings

A Lone Wolf

Fangs

The Misty City

Resistance Movement

The Crimson Magician

Escape!!

The Power of the Ancient Civilisation

The Three Ordeals

Kirin?!

Two Against One

Go, Bat-man!!

Mexis Activated!!

The Power of a God

Marching Along the Winding Road

Everybody's Thoughts and Feelings

Final Operation

Everybody's Hearts as One

A Pact With the Devil

Archenemy

Blue Sky

Gaiden: Justice

The Legend of Spirit

Kabbalah

Mum and Dad

Black Market Caravan

The Fated Two

The Kabbalah's Angel

Olympia's Prelim Round

The Chosen Two

Rock Bird

The Main Round Begins

The Promise

Maximum Volume

A Real Monster, Part 1

A Real Monster, Part 2

The Bird Inside a Cage

The Shape of One's Heart

Hope

Rival!?

Theory of the World

The Big Bang

Top Floor

Evil King Icarus

Heart

Kaballah's Devil

Figure

1 Hit

Light and Dark

The Key of Solomon

Bonds

Ancient People

Legendary O-Parts

New Member

Break In!

Everyone's Fight

Magic Trick

Miko's Truth

Welcome Home

All Members Gather

Full Moon

Zenom's Headquarters

The Ruins' Traps!

Brothers Face Off! Memories of the Scars!

Father's Thoughts

Life

The Heart of a Woman

Devil's Summoner

2 Battles

Zenom

Pinky Swear

Armageddon

Jio Freed

In the not too distant future, mankind battles over O-Parts, relics from an ancient civilization. It takes a special kind of person to unlock the full potential of these remnants from the past, and a unique breed of humans known as O.P.T.s (or O-Parts Tacticians) become a force to be reckoned with. Unfortunately, O-Parts can be used for good or 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, 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?!
 
(Source: Viz Media)
 
Notes: 
- Includes 1 extra story. 
- Includes the one-shot "Trigger" (トリガ)