The girl warrior Fania meets a young man with amnesia named "Tutor", and the two embark on a journey together, gradually revealing the secret of the enemy - "Alien". At the same time, it is also discovered that "a certain mysterious force" hides behind it and wants to control the life of the girl warrior "Slude". They decided to rise up and purify the land...

After his high school graduation, Yuuki Wakura realizes it has been five years since his sister's disappearance during a "Mato disaster." Throughout Japan, mysterious entrances have opened to a dimension called "Mato"—a demonic metropolis filled with disastrous monsters known as the "Shuuki" that threaten the safety of humans. However, a new hope arose, as the discovery of a Mato fruit that grants supernatural abilities exclusively to women allowed them to fight against the Shuuki. Due to this, a new matriarchal government was formed, establishing a female organization called the Anti-Demon Corps, which caused men to fall to the bottom of society. When Yuuki suddenly finds himself in Mato, he is unable to escape on his own. But just as he anticipates a gruesome end by the Shuuki, a girl in a militia outfit appears and protects him. As the chief of the Seventh Unit of the Anti-Demon Corps, Kyouka Uzen is ambitious yet devalued by her own peers due to her power being deemed unusual. Now in a life-or-death situation, Kyouka takes the opportunity to find out the true potential of her superpower by using Yuuki: in order to defeat the Shuuki, he has to become her slave.

At True Cross Academy, Rin Okumura unknowingly comes across the first signs that something is amiss; ordinary people have been gaining the ability to perceive the invisible creatures that roam the human realm, Assiah. While Rin sees this as an opportunity to make a new friend, his twin brother, Yukio, is more burdened than ever. Swamped with his education, exorcist duties, and teaching position, Yukio has remained silent about his awakened powers, unable to understand their scale or significance. While Rin and his friends prepare for the annual Exorcist Certification Exam, the True Cross Order has uncovered the first artificial gate to the demonic realm of Gehenna. Witnessing its size and the advanced technology that made it possible, the exorcists realize they are now dealing with the Illuminati, an extremely wealthy and powerful organization. Moreover, the inscrutable Illuminati have planted three spies in the True Cross Order—and one may be hiding among the aspiring exorcists sworn to protect mankind from the demonic threat.

Rud is a tank of the Hero's Party and is said to have the highest defense ever in history. The party often does labyrinth raids, but to Rud, it means more than just a raid. To cure his beloved sister's illness, he is in search for the wish-granting treasure that might be hidden in those labyrinths. But one day, the arrogant hero kicks him from the party after an unsuccessful raid attempt, blaming it on his skills whose effects he is still unaware of. Without nowhere else to go and nothing to do, he decides to return to his hometown, where his sister is waiting. On his way there, he saves a girl who was being attacked by a monster. Unexpectedly, this girl has an extremely rare skill called "Appraisal." Thanks to her skill, Rud is able to discover the truth behind his unknown skills, which turn out to be very powerful skills. With a defense of 9999 and powerful skills, thus begins the adventure of the strongest tank, Rud!