Ushio Aotsuki is a stubborn middle school student and son of an eccentric temple priest who goes about life without care for his father's claims regarding otherworldly monsters known as youkai. However, as he is tending to the temple while his father is away on work, his chores lead him to a shocking discovery: in the basement he finds a menacing youkai impaled by the fabled Beast Spear. The beast in question is Tora, infamous for his destructive power, who tries to coerce Ushio into releasing him from his five hundred year seal. Ushio puts no trust in his words and refuses to set him free. But when a sudden youkai outbreak puts his friends and home in danger, he is left with no choice but to rely on Tora, his only insurance being the ancient spear if he gets out of hand. Ushio and Tora's meeting is only the beginning of the unlikely duo's journey into the depths of the spiritual realm. With the legendary Beast Spear in his hands, Ushio will find out just how real and threatening the world of the supernatural can be.

Valkyries—legendary female warriors from the land of gods, Asgard—are sent by Odin to protect Earth against the growing threat of demons. To overcome these threats, nine valkyries under the guise of the Saotome sisters will have to level up by performing a variety of romantic acts with their official lover, Einherjar. Meanwhile, the socially anxious Takuma Akutsu learns that Odin has chosen him as the valkyries' lover. Despite his utter horror, however, he agrees to let the sisters stay in his big yet empty house to help them in their war against demons. With nine beautiful women sharing his roof, will Takuma manage to prevail over his fear of society and become someone worthy of saving the world?

Vanitas and Noé Archiviste head out to the town of Gévaudan in search of the Beast, an enormous wolf-like creature that has slaughtered hundreds of people. Suspecting that the Beast is a curse-bearing vampire, Vanitas primarily aims to heal it using the powers of his grimoire. Along the way, the two get separated and suddenly travel back to the past—to the exact moment the Beast is lurking in the woods. After a battle against the gigantic wolf and a vampire hunter, Vanitas decides to team up with Jeanne in order to find Noé. Despite being allies, Jeanne's goal is the opposite of Vanitas', as she was tasked to kill the Beast—suspecting it may be someone she used to know. Meanwhile, a severely wounded Noé is picked up by the mysterious Chloé d'Apchier and her servant. Like Noé, Chloé is a vampire whose existence was erased from the public's knowledge. She has been a guardian for future generations and once tried to find a way to become human again. While Noé is grateful to Chloé for her hospitality, little does he know that she might be siding with forces far more dangerous than the Beast itself.

Scorned by others of his kind for being born under a blue moon, the vampire Vanitas grew afraid and desolate. According to legend, he created a cursed grimoire known as the Book of Vanitas, and it is said he would one day use it to bring retribution upon all vampires of the crimson moon. In 19th century Paris, Noé Archiviste is searching for the fabled Book of Vanitas. Whilst traveling aboard an airship, he is saved from a vampire attack by an eccentric doctor who calls himself Vanitas and carries the very tome he seeks. Ironically, the self-proclaimed vampire specialist is a mere human who inherited both his name and the book from his master, the same Vanitas of legend. As the odd case of the Charlatan's Parade crops up, the doctor's ability to restore sanity to vampires by recovering their true name will prove most beneficial.