Satoko Kusagakure, a female ninja who left her village with her comrades, finds herself living with Konoha, a high school girl working as an assassin in the city. Satoko possesses the ability to transform objects using ninjutsu, which catches Konoha's attention. They strike a deal: Konoha provides Satoko with a place to live in exchange for Satoko's help in cleaning up after her assassination jobs. As they face off against assassins sent by Satoko's village, indulge in delicious meals using money earned from assassination jobs, and navigate the chaos of their unusual living situation, the story captures the heartwarming yet chaotic lives of these two unlikely roommates.

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.

Many years have passed since humanity vanished from Earth, yet the Galaxy Tower hotel in Ginza, Tokyo, continues to operate. At the center of its staff is Yachiyo, a dedicated hotelier robot, along with other employee robots working tirelessly in various departments. Together, they spend what feels like an eternity maintaining the hotel, despite having no guests. As they await the return of their owner and the day humanity reappears. Now, a small miracle is about to change everything for Yachiyo and her robotic colleagues.

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...