12,000 years after the events in Genesis Aquarion, humans live on the star Vega under constant threat of trans-dimensional beings called Abductors. These enemies originate from Vega’s sister star Altair and raid Vega for human life. As a countermeasure, an organization known as Neo-DEAVA formed to combat the Abductors. They pilot advanced mecha suits called Aquaria and are strictly separated by gender. Boys and girls are not allowed contact; they are even restrained from fighting on the same battlefield. However, events take a shocking turn when an advanced Abductor mecha suit joins the fray. Two teenagers, Mikono and Amata, are dragged into the conflict. Unknowingly, Amata performs a taboo when he summons an Aquaria and initializes what is called the Forbidden Union between male and female Aquaria. Neo-DEAVA is shocked, and the repercussions of Amata’s actions are much farther reaching than he realizes. How was he able to summon an Aquaria? Where did he learn to form a Forbidden Union? And why was Mikono also able to pilot the mecha suit?

1. Batsukoishi-hen 2. Ayakashisenshi-hen 3. Musubienishi-hen 4. Yumeutsushi-hen

One day after school, first-year high school student Yomogi Asanaka comes across a starving man under a bridge. Introducing himself as Gauma, the strange drifter informs Yomogi that he is a kaiju user, a person who deals with the kaiju—monsters who bring harm to the city and its citizens. The following evening, Yomogi runs into Gauma and his classmate Yume Minami. Simultaneously, a kaiju appears in a populated area of the city. Due to Gauma's lack of experience controlling the kaiju, he brings out a mysterious object from a glowing pouch, summoning a giant robot known as Dynazenon. Requiring the cooperation of four people, the mecha drags Gauma, Yomogi, Minami, and Koyomi Yamanaka—an unemployed man who was wandering on the street—into its cockpit. Their encounter with the kaiju marks the beginning of their entanglement with kaiju eugenicists—kaiju users who manipulate kaiju with ill intent—and their efforts toward bringing out the full potential of Dynazenon.

In a war against four overpowered races—angels, demons, undeads, and humanoid beasts—humanity could only prevail thanks to its champion Sid, who defeated the other races' champions and sealed away their armies in four pyramids. In an age where Sid's existence has become but a legend of the past, Kai Sakura Vento is one of the many conscripts tasked with monitoring the pyramids in fear that these old foes would escape. On a peaceful day while spending time with his friend Jeanne E. Anise, the world is suddenly overwritten, transporting Kai to an alternate reality where humanity has nearly been annihilated by the demons and forced into hiding. To make matters worse, his very existence has been erased from this world; all of his friends, including Jeanne, who leads the local resistance efforts in this world, have forgotten about him. Trying to investigate the remains of his former world, Kai encounters Rinne, an enigmatic young woman trapped in a pyramid. Mysteriously inheriting Sid's legendary sword Codeholder, Kai manages to free Rinne from her imprisonment. Determined to fix this reality, Kai joins forces with Rinne and Jeanne to free humanity from demonic rule. But if the valiant soldier wants to have a chance at returning to his original world, he will first have to uncover the cause behind the mysterious alteration of reality.