Since the death of his parents, Shinpei Ajiro had lived with the Kofune family and their two daughters—Mio and Ushio. Although he then left his home island to continue his education in Tokyo, Shinpei returns after Ushio tragically drowns during the attempted rescue of a little girl. During the funeral, his best friend informs him about bruises found around Ushio's neck, casting doubt over the cause of her death. Suspecting a murder has taken place, Shinpei reevaluates recent events, but strange incidents only continue to transpire. Disappearing people and other unexplainable occurrences lead Mio to recall an old folktale referring to entities called "Shadows," which may not be entirely fantasy. Supposedly, an encounter with one's Shadow foretells the person's impending demise. Facing the dark side of Hitogashima Island, Shinpei stands against his grim fate to fulfill Ushio's final will—to protect Mio.

Cursed by a witch as a child, a young duke gained the unwanted power to kill every living thing he touches. Forced to move away from his family and into a large mansion deep in the woods, the duke is treated as if he does not exist and is continually shunned by his peers. However, he is not entirely alone. Rob and Alice, his butler and maid, are always by his side. Alice loves to tease him, and as their relationship grows, the duke makes it his goal to break free from his deadly curse. Of course, he is going to need some help, and who better to do this than the various inhabitants of the supernatural? [Written by MAL Rewrite]

Zenitsu Agatsuma is determined to be the subject of adoration by receiving chocolates on Valentine’s Day—and this year, he is taking no chances. Enlisting the help of his friend Tanjirou Kamado, the two are prepared to learn from some of Kimetsu Academy's most popular figures. Together, they ask Kyoujurou Rengoku, the history teacher; Giyuu Tomioka, the PE teacher; and Tengen Uzui, the art teacher, about the secrets to their popularity. However, only time will tell if following their advice will bring the same success for Zenitsu.

This is a story of connecting shining emotions. Joy, sadness, anger. Feelings are a power, invisible to the eye, that every person possesses. Sometimes this power is even capable of changing the world. Hiori Hirahara always has a positive attitude and can't leave people in trouble alone. Ruki Hanari is socially awkward, she wants to get along well with others, but she doesn't know how to go about it. How will the meeting of these two wildly different girls change not only them, but the world itself?