After the mysterious mana calamity, Rudeus Greyrat and his fierce student Eris Boreas Greyrat are teleported to the Demon Continent. There, they team up with their newfound companion Ruijerd Supardia—the former leader of the Superd's Warrior group—to form "Dead End," a successful adventurer party. Making a name for themselves, the trio journeys across the continent to make their way back home to Fittoa. Following the advice he received from the faceless god Hitogami, Rudeus saves Kishirika Kishirisu, the Great Emperor of the Demon World, who rewards him by granting him a strange power. Now, as Rudeus masters the powerful ability that offers a number of new opportunities, it might prove to be more than what he bargained for when unexpected dangers threaten to hinder their travels.

The ordinary life of 17-year-old otaku Hajime Nagumo is disrupted when he and his classmates are summoned to a fantasy world and tasked with saving mankind. While his classmates are gifted with impressive abilities useful in combat, Hajime is belittled for only gaining an inferior transmutation skill that lacks any real offensive power. During an expedition in the Great Orcus Labyrinth, Hajime is betrayed by one of his classmates, plummeting him to the bottom of an abyss. Though he survives the fall, Hajime is faced with menacing monsters and misfortunes that send him spiraling into a grim nightmare. Desperate to live and return home one day, he resolves to fight for his survival—only to meet an imprisoned vampire he names Yue, who is also seeking to escape the labyrinth. Taking an interest in him, Yue and a few others along the way accompany Hajime on his journey to find a way back home, while steadily transforming from commonplace to the world's strongest. [Written by MAL Rewrite]

Kou Yamori is an average middle school student who struggles with grasping the complex concept of love. Because he sees little sense in surrendering to the norm, he soon stops going to school. Plagued with insomnia due to his idleness, Kou begins roaming the lonesome streets at night. One night, Kou encounters a bizarre girl named Nazuna Nanakusa who believes that people stay awake during the night because they are dissatisfied with how they spent their day and cannot rest until they release their inhibitions. Nazuna offers to help Kou with his sleep issues and invites him over to her place, where she convinces him to share a futon with her. Feeling uncomfortable, Kou only pretends to doze off—which is when Nazuna suddenly bites his neck and reveals herself to be a vampire! While Kou thinks the bite will turn him into a vampire, the specifics of transforming are not that simple. In order to change, he must be bitten by someone he truly loves. Ready to let go of his dreary mortal life, Kou decides on a new goal: he will fall in love with Nazuna and become a vampire.

After his father's death and the destruction of his village at the hands of English raiders, Einar wishes for a peaceful life with his family on their newly rebuilt farms. However, fate has other plans: his village is invaded once again. Einar watches helplessly as the marauding Danes burn his lands and slaughter his family. The invaders capture Einar and take him back to Denmark as a slave. Einar clings to his mother's final words to survive. He is purchased by Ketil, a kind slave owner and landlord who promises that Einar can regain his freedom in return for working in the fields. Soon, Einar encounters his new partner in farm cultivation—Thorfinn, a dejected and melancholic slave. As Einar and Thorfinn work together toward their freedom, they are haunted by both sins of the past and the ploys of the present. Yet they carry on, grasping for a glimmer of hope, redemption, and peace in a world that is nothing but unjust and unforgiving.