The Gates of Hell reopen, throwing the world into chaos and setting demons free to terrorize the land once again. These troubles seem irrelevant to quirky villager Touka Scott—until a demon attacks Yuna Eunice, his childhood friend. Luckily, the legendary hero Sion Blandan arrives in the nick of time to strike down the vile creature. Unfortunately, Sion soon dies after accidentally falling into a trap Touka set to defend his radish farm. Anri Haysworth, Sion's necromancer companion, resurrects the hero by transferring Touka's soul into Sion's corpse. Now possessing the body of the legendary hero, Touka is tasked with resealing the Gates of Hell and defeating the demons that threaten peace. Together with Yuna and Anri, Touka copes with both his new reality and Sion's heroic legacy as he embarks to save the world.

Among all the beasts that roam the world, there are unique types of ultimate species that harbor immense strength and magical prowess considered to be at the top of the power scale. As such, many humans covet their abilities, leading some of these species to the brink of extinction. As a beast tamer, Rein Shroud can employ the assistance of various animals for many tasks, such as reconnaissance and logistics. By virtue of his ability, he joins a party led by the vile and manipulative hero Arios Orlando, only to be banished after six months due to his uselessness as a non-combative class. However, unbeknownst to the team that cast him away, Rein is an exception among beast tamers. His potential becomes apparent when he meets Kanade—a cat spirit who is also one of the ultimate species—and is able to form a contract with her. With Kanade by his side, Rein sets out on his journey as an adventurer, steadily rising up the ranks and meeting more ultimate species along the way.

Following Gutsy Galaxy Guard's victory over the Zonder Empire and the 31 Primevals, a new threat makes their appearance on Earth. GGG - with Guy Shishio and the newly-constructed GaoFighGar - team up with their French counterpart Chasseur to battle the evil organization BioNet. Among Chasseur's ranks is Renais Cardiff Shishioh - a former BioNet cyborg with the relentless pursuit of destroying those who took away her humanity. But as GGG and Chasseur fight the BioNet, GGG's bases around the world are suddenly attacked, and the recently-discovered Q-Parts and the original Gao Machines are stolen by Mamoru Amami, who has been abducted and cloned by an even greater threat known as the Eleven Kings of Sol. Evicted from Earth by the United Nations, GGG must now travel to the far reaches of the galaxy to battle the Eleven Kings of Sol and save Mamoru before it's too late. (Source: ANN)

After a slumber of 12 millennia, the Demon Empire returns to seize control of the Earth. Reideen, the giant robot-like protector of the lost continent of Mu, senses the evil presence and awakens within its golden pyramid, revealing to young Japanese boy Akira Hibiki that he is the one descendant of the ancient Mu people who must help Reideen save Earth. He was assisted by his friends, token girl Mari Sakurano (daughter of a scientist fighting the Demon Empire) and several members of his high school soccer team. (Source: AniDB)