As the grand festival of True Cross Academy draws near, exwires and exorcists alike combine their efforts to banish any demon that threatens the celebrations. Among them, Rin Okumura is tasked with exorcising the soul-devouring demon known as the Phantom Train alongside his brother Yukio and Shiemi Moriyama. During their mission, the Phantom Train escapes its tracks and begins ravaging True Cross Academy. In the ensuing chaos, Rin encounters a childlike demon he dubs Usamaro, and begins to develop an odd friendship with it. However, Usamaro's abilities might be far more sinister than Rin initially expected.

Despite completing all the tasks given to them, Ainz Ooal Gown, Tanya Degurechaff, Kazuma Satou, Subaru Natsuki, and the other members of Class 2 are surprised to find out that their role as students is far from over. With no means of returning home, the class of eccentric personalities is still mysteriously stuck in the unfamiliar world. Although, as they are becoming quite fond of each other, spending more time together does not sound that bad. With the unexpected arrival of new transfer students, the comedic antics of our beloved characters continue to grow. Thus, their bizarre yet nonchalant school life continues.

A nameless sword wakes up to discover he has been reincarnated from his former life as a human. With his power of telekinesis, he moves around this new world, acquiring several skills and abilities. When the sword comes upon a forest filled with monsters, he meets a young girl fleeing from a beast. Grabbing the sword, the girl easily defeats the monster. After introducing herself as Fran, she names the sword Shishou and officially becomes his wielder. The two set out to become adventurers, but unfortunately for Fran, she is a member of the Black Cat Tribe—a Beastkin group with a bad reputation. No member of this tribe has ever evolved into a mightier beast, but Fran plans to be the first and achieve her parents' dream. As Shishou promises to remain her sword until she attains her goal, they form an unstoppable partnership of impressive strength.

In his past life, Prince Lloyd de Saloum was a commoner who could not become adept at magic, no matter how knowledgeable or obsessed he was about it. Now reincarnated into his current royal lineage, he receives a body with seemingly endless mana, making his desire to master all things arcane attainable. Moreover, as the seventh prince of the kingdom, Lloyd has no claim to the throne, allowing him to nurture his abilities as freely as he wants. Unfortunately for Lloyd, ancient seals that imprison powerful demons begin to break down and release the horrors within, endangering the peace. With these monstrosities roaming around, Lloyd's overwhelming magical prowess is the ultimate weapon that can neutralize these threats before all things descend to chaos.