The day is as normal as it can be in high school as the students peacefully go about their everyday activities until an unprecedented catastrophe strikes the school, killing every person in its wake. Guided by what seems to be a miracle, a handful of students are fortunate enough to be reincarnated into another world as nobles, princes, and other kinds of people with prestigious backgrounds. One girl, however, is not so lucky. Being reborn as a spider of the weakest kind, she immediately experiences the hardships of her dire situation. Even so, she must press on to survive the numerous threats that endanger her life. Discovering that her new world has a system like that of an RPG, she tries her best to hunt prey and defeat monsters to level up and evolve. As she gradually grows stronger, she hopes one day her efforts will be rewarded, and that she will be granted a better life.

The virtual world inside the scub coral (intelligent coral-like lifeforms) created by Eureka... The people from that virtual world appeared on Earth ten years ago when it collapsed. Since this large-scale amalgamation, the humans from the virtual world call themselves "Green Earth" and the original Earth humans call themselves "Blue Earth," and they've come to cause various conflicts with each other repeatedly below the surface. Eventually, Dewey Novak, a senior officer in the Green Earth Armed Forces, rises together with his comrades and finally sets a large-scale terrorism plan into action in order to protect their own dignity. Meanwhile, Eureka, who is detested by the world as the main cause of the chaos, has become a high-grade combatant with the UN's A.C.I.D. unit. Live in order to keep this world at peace... This was the path of atonement she chose. One day, she receives an order to protect a girl named Iris, a new "Eureka" who has the ability to control scab coral. They fight a lot at first but gradually come to understand each other through their lonely escape. Soon the world faces a crisis, and when that happens, Eureka draws on every last ounce of her strength as she fights. "I want to protect Iris and this world." What future awaits her at the end of that wish of hers?

Three years into the war, Mahito Maki loses his mother in a tragic fire at the hospital. Shortly thereafter, his father marries Natsuko, the younger sister of Mahito's mother. They take Mahito out of Tokyo to seek refuge in his late mother's rural family home. There, Mahito is constantly taunted by a strange gray heron, who seems to have taken an interest in him. Unable to come to terms with his loss and struggling to adjust to a new life in an unfamiliar place, the boy is shocked to discover that Natsuko is pregnant. To make matters worse, the pesky heron can speak—and claims that Mahito's mother is still alive. Luring him into a mysterious tower near the residence, the heron says that Mahito can save her from death, but the boy is not easily swayed. When Natsuko disappears one day, however, Mahito watches her walk into the tower and becomes compelled to venture in to rescue her. He soon finds himself falling into another world below his, where life and death seem to be entwined. As he navigates through this foreign realm to find Natsuko, Mahito must understand what it means to live if he wants to safely return home.

After a string of mysterious disappearances begin to plague a train, the Demon Slayer Corps' multiple attempts to remedy the problem prove fruitless. To prevent further casualties, the flame pillar, Kyoujurou Rengoku, takes it upon himself to eliminate the threat. Accompanying him are some of the Corps' most promising new blood: Tanjirou Kamado, Zenitsu Agatsuma, and Inosuke Hashibira, who all hope to witness the fiery feats of this model demon slayer firsthand. Unbeknownst to them, the demonic forces responsible for the disappearances have already put their sinister plan in motion. Under this demonic presence, the group must muster every ounce of their willpower and draw their swords to save all two hundred passengers onboard. Kimetsu no Yaiba Movie: Mugen Ressha-hen delves into the deepest corners of Tanjirou's mind, putting his resolve and commitment to duty to the test.