Ryusuke is a junior high school student living in Tokyo. During his summer vacation, he visits Tokushima and reunites with his teenage cousin, Tomomi. Ryusuke and Tomomi go outing to the Anabuki River where they get swept away by the rushing current. As they sink to the bottom of the river, a dragon appears, rescues them, and takes them to a mysterious old man. The old man tells Ryusuke and Tomomi that they are already dead, but that he can send them back to life if they explore the spirit world and find their mission in life. Although perplexed with the situation, Ryusuke and Tomomi decide to begin their journey to the spirit world. First, they arrive in a gloomy town that looks like it’s from the 1960’s. Soon after, they are assailed by terrible things one after another. They see fear-ridden rogues killing one another and doctors mutilating patients. People die and rise. They get killed and rise again. Ryusuke and Tomomi realize that they are in hell. But their journey doesn’t end there. The adventure beyond this world continues into the unknown. Will they be able to find their mission in life?

It's a time of warfare where relentless battles continue between human and demi-human tribes like the Ash Monkeys (Macaque) and pig people (Ogres) invading human lands. Kai, a boy from the village of Rag, spends his days immersed in battle to protect his village. Amidst the harsh battles enforced by those possessing immense power known as "guardian bearers," and as his comrades fall one by one, Kai suddenly recalls memories he shouldn't have experienced—memories of a world with advanced technology and knowledge of people's lives beyond this world. And thus, although Kai was just a villager, he soon finds himself embroiled in great trials... A magnificent fantasy tale unfolds, chronicling the struggle and growth of a single boy in a harsh world.

This is a world where heroes are created by people's trust, and the hero who has received the most trust is known as - X. In this world, people's trust can be calculated by data, and these values will be reflected on everyone's wrist. As long as enough trust points are obtained, ordinary people can also have superpowers and become superheroes that save the world. However, the ever-changing trust value makes the hero's path full of unknowns...

Deep in a tropical jungle, young Yaiba Kurogane diligently practices swordsmanship alongside his father, Kenjuurou, completely unaware of the modern world. However, one day, the two end up in a container on its way to Japan. There, they encounter Kenjuurou's old rival, Raizou Mine, and his daughter, Sayaka. Out of other options, Yaiba agrees to a deal with the Mine household: if he beats the strongest student in their dojo, he will be welcome to stay. Using his distinctive skills and extraordinary strength, Yaiba earns his place. Wanting to fight more powerful enemies, Yaiba follows Sayaka to school—where he quickly loses to Takeshi Onimaru and acknowledges him as his new rival. With Onimaru inheriting the sword of his bloodline and obtaining demonic powers, Yaiba must train to become even stronger and beat him for good.