Clay has been undergoing intense training for the past three years to track down her father, who was last spotted exploring a dungeon. Any normal adventurer finds dungeon delving challenging, but Clay is aware that her father, a thief who doesn't only use magic or brute force, made more progress than anybody else. He leaves, and Clay follows him till she comes to a furnished room behind a dungeon wall. Clay is startled to see that the room is teeming with talking creatures and a girl posing as the dungeon administrator. But the purpose of the room is to keep explorers from seeing it. Clay is hired to work for them now that she is aware of the dungeon's secret. Even though she didn't anticipate landing a job during her journey, doing so might help Clay solve the mystery surrounding her father's absence.

Five extraordinary mages known as the Heavenly Invaders banded up to battle strange enemies that enslaved humanity. The five strongest magicians, known as the Magia Vander, constructed a tower and a magical dome to keep these fierce foes out of the area because they were afraid they might return. From the top of the Wizard's Tower, the five most powerful mages of each generation are now assigned to keep watch over the dome. This tale inspired Will Sefort and Elfaria Albis Serfort, who were childhood friends, to make a vow to one another that they would ascend the Wizard's Tower. Will, a sixth-year student at Regarden Magic Academy, has a dismal future ahead of him. Elfaria's unmatched magical talent allowed her to enter the Magia Vander five years ago, but Will lacks any magical skills at all, which infuriates both teachers and pupils.

The only way mankind could win a war against four overpowered species—demons, undeads, angels, and humanoid beasts—was if its champion, Sid, vanquished the champions of the other races and imprisoned their armies in four pyramids. In a time when Sid's existence is but a myth, Kai Sakura Vento is one of the numerous conscripts assigned to guard the pyramids out of concern that these ancient enemies might break free. While spending time with his companion Jeanne E. Anise on a calm day, the universe is abruptly "overwritten," taking Kai to another reality in which the demons have all but destroyed humanity and driven people into hiding. Even worse, his very existence has been wiped out of this world; Jeanne, the leader of the local resistance movement in this reality, and all of his companions have forgotten about him.

While working as a massage therapist, Tomoatsu Naoe enjoys a routine life until he meets Erufuda, a strange customer. Naoe learns her secret—that she is an elf—during her visit! Erufuda fell in love with junk food after leaving her world and now she is unable to go back since she has gained too much weight. In order for the elf to eventually return to her realm, Naoe chooses to assist her with dieting. Even though Erufuda works hard and succeeds, Naoe soon finds her again and she has gained the weight back. The two start meeting people from another world who share their goal to reduce weight as Naoe keeps giving them guidance.

Kimihiko Kimizuka often finds himself in the midst of trouble, having unintentionally become involved in numerous crimes more often than he can remember. He is abducted by a bunch of unidentified guys one day, as if it were nothing unusual, and is forced to board a plane, where he is also hijacked. But in the middle of the ensuing mayhem, he runs into a gorgeous woman with silver hair who goes by the codename Siesta, who ends up saving the day. Siesta hires Kimizuka as her partner, claiming to be a legendary detective. Despite his initial refusal, Kimizuka eventually agrees to accompany her at Siesta's request, signaling the beginning of a big global journey that avoids several dangers that may otherwise signify the end of civilization. Tragically, Siesta dies suddenly after three years of their erratic yet fun time together. Distressed, Kimizuka makes an effort to forget about her, but as he starts to interact with other people, it appears that Siesta's influence will always be there.

The untamed and unpredictable Guideau, cursed by a witch, is on a relentless quest for vengeance against her curser. She joins the Order of Magical Resonance, an organization dealing with all magical affairs, to aid her search. In return for Guideau's help with the rising number of magical incidents around the world, the Order agrees to assist her. Accompanied by Ashaf, a suave and mysterious magician from the Order, Guideau embarks on various missions. As they journey through the wilds in search of the elusive witch, their experiences with the magical world grow increasingly bizarre.

The deity of wind, Silphyleel, accidentally murders Takumi Kayano, age 28, as a result of a thoughtless error. Takumi cannot, regrettably, be brought back to Earth by Silphyleel. Rather, the god brings Takumi back into the fantastical realm of Etelldia. High-level enemies roam freely in the Forest of Gaia, where Takumi spawns with a bottomless inventory and a variety of magical abilities. He encounters five-year-old twins there who, in part because of their exceptional athletic prowess, are still alive in spite of the hazardous surroundings. Takumi chooses to adopt them and names them Elena and Allen. Their very presence could affect the fate of the world as the three set off on their epic journey in Etelldia.

A truck hits renowned writer Sensei, taking him to a different realm, just as he is about to fulfill his lifelong dream of killing himself and his partner Sacchan. The difficult task of killing the demon king is handed to Sensei, who the local priestess Annette regards as an adventurer. Sensei, unwilling to embrace his new status, determines that it would be preferable to search for Sacchan in the hopes that she may be in this new world. Sensei meets martial artist Tama early in his travels and unintentionally saves her from certain death. Tama, appreciative of his deeds, chooses to accompany him. Annette soon joins the two after being drawn to the writer's assertive nature and promising to keep Sensei alive. The unusual three quickly comes to the conclusion that humans may actually be the real threat to global peace, and that Sensei may be the only one who can stop them, as they travel through perilous, monster-infested areas.

Shinya Kiritani, an expert player in the virtual reality game The New Gate, is stuck alongside hundreds of other players and decides to finish the game in order to go back home. But after defeating the last boss by himself, Shinya finds himself in a new world that doesn't seem to be much different from the one he just left behind. Shinya finds that he is stuck in this strangely familiar world as long as the game menu remains the same and his skills remain the same. Shinya meets Tiera Lucent, a hotel receptionist and Schnee Raizar's protégé, while trying to figure out how to escape this new spatial prison. Schnee Raizar was once a member of Shinya's party. With this ray of hope, Shinya sets out to discover the truth about The New Gate and get back together with Schnee.

Kazuya Souma, a 19-year-old who aspires to be a civil servant, is left all alone and without relatives when his grandfather passes away. Without warning, he is sent to the tiny, sickly nation of Elfrieden Kingdom on another world to play the role of "hero." The planet is in danger due to a continuing battle with the demon army, and Elfrieden called Kazuya to fight alongside its allies. Unhappy to be treated like a slave, Kazuya resolves to assist the kingdom in reviving its failing economy by administrative reform rather than via adventure or conflict. Suddenly crowned King of Elfrieden and engaged to the princess, "Realist Hero" Kazuya sets out to gather a cadre of gifted citizens to help him fight his bureaucratic fights and rebuild the kingdom.

Allen is dethroned from his noble position and exiled from the Duchy of Westfeldt because he is perceived as a "good-for-nothing" due to his low level and absence of a divinely bestowed Gift. Allen, nevertheless, is hiding something from you: he was a fantastic hero once, and he is ecstatic to be able to live his life as he pleases! But his drama-free life is suddenly cut short when he has a desperate meeting with his ex-fiance. Even though he would like to, Allen, a former hero with amazing abilities from a previous life, can't turn away someone in need! The new heroic story that our old hero never desired has begun!

For almost sixty years, Shouzou Saitou and his spouse, Ine, have been together in marriage. Their love has remained strong even though they haven't amassed fortune or been able to take a honeymoon in all that time. The couple enjoys visits from their devoted family while living a tranquil life tending to their apple tree orchard. A golden apple is seen hanging from one of the limbs of the apple tree the couple planted on their wedding day, which broke in half during a typhoon. After returning home and finishing the apple, the couple discovers they have aged backwards the next morning! Shouzou and Ine are able to live their lives as they never have before in their new, comfortable bodies. They play video games and take part in more contemporary activities like attending sports festivals. Their affection is reignited as they reminisce about their early years together, and the younger members of their family begin to feel the same way.

With the passing of its oldest member, Marchosias, the formidable but young sorcerer Zagan is vying to join the ranks of the world's strongest sorcerers, the 13 Archdemons. Zagan discovers something unexpected while visiting the estate auction of the late Archdemon: love at first sight. To return Nephelia, a rare elf slave, to his castle, the sorcerer impulsively spends all of his money. With the girl's enigmatic and troubling past, Zagan has a lot to learn about his new friend. But because Zagan has never experienced the strange sensation of love, he and Nephelia—whom he refers to as "Nephy"—have a lot of awkward moments. It's becoming more and more obvious that Nephy and Zagan's feelings aren't all that dissimilar as they get to know one another better.

After being accidentally awakened from her slumber within a glacier, the dragon god Leoleshea demands to meet the era's greatest gamer. A year later, she encounters Fay Theo Philus, an apostle. An Arise is a supernatural ability granted to a person, enabling them to challenge the gods in games. Fay and Leoleshea discover their mutual enjoyment of gaming, whether it's a card game or a battle of wits with a deity. Leoleshea consents to be called "Leshea" by Fay and joins in the divine games, expressing fondness for this human. The gods have vowed to grant any wish after 10 victories, ever since they gave mortals the power to contend with them. Leshea, having once descended to the human realm and lost her divine status, yearns to reclaim her recognition as a god. Meanwhile, Fay's primary goal is to find the woman who long ago taught her the art of gaming. The gods will not let Leshea and Fay to win ten games so easily, even though they rapidly show themselves to be a formidable team.

Being an adventurer in a party is one of the most sought-after vocations in a world where monster invasions are common and prevalent because of the prestige and honor it confers. A young human warrior named Alvin wants to establish himself, so he plans to begin by finishing a low-level request for the guild. Alvin encounters a supernatural bear while traveling and finds himself in a tight spot right away. By chance, a dark elf healer by the name of Karla appears and inquires as to whether Alvin needs help; she doesn't appear to be aware of what is going on. After a convoluted conversation made more difficult by Karla's ridiculously quirky demeanor, Alvin manages to persuade her to assist him. Regretfully, she unintentionally curses him, saying that he would perish if he ventured too far from her. Alvin's desire to become a true explorer does not waver, even if he must travel with Karla until the curse is lifted.

Kimito Kagurazaka is a regular man who has a weakness for the muscles of males. Or at least that's what he has to tell himself to get out of trouble at Seikain Academy, an exclusive school for girls. Kimito is made to serve as their "commoner sample," exposing the girls to both commoners and men so that the transition to life after school is not too abrupt. He is abducted by the school on the grounds that they think he favors men. Fearing that he might be castrated if his sexual choices did not align with the school's presumptions, Kimito maintains his façade in order to preserve his masculinity. However, Kimito's life becomes much more challenging as strange people appear out of nowhere. Reiko Arisugawa, the ideal student with fantasies of marrying Kimito, Karen Jinryou, the daughter of a samurai who is obsessed with beating Kimito, Hakua Shiodome, a young prodigy, and Aika Tenkuubashi, a social outcast who blurts out anything that comes to mind, are among them.

Every year, hundreds of heroes from other planets are called to battle in the Magical Kingdom of Klyrode against the Dark One and his army of formidable demons. One of those heroes, Banaza is called upon from the Paluma Royal Capital, but something is wrong because Banaza is just a regular shopkeeper. In addition to lacking fighting prowess and magic, his stats are awful. Even worse, an accident prevents him from going home! Banaza's fate appears to be rather grim: he is despised as a hero and left trapped in an alternate world, abandoned to the outer corners of the kingdom by a ruthless ruler who simply wants him dead. What will happen, though, when the failed hero candidate reaches level two and discovers he has super cheat powers?

Following the devastation of their hometown, childhood friends Kafka Hibino and Mina Ashiro decide to enlist as officers in the Defense Force, a menacing military agency entrusted with defending Japan against enormous creatures known as "kaijuu." Thirty-two-year-old Kafka had all but given up on his heroic ideals after all these decades. Rather, he cleans up the carcasses of the slain kaijuu after they are vanquished by brave troops, one of whom is Mina, who has accomplished their mutual objective. When Kafka first meets Reno Ichikawa, his new coworker, he encounters a reflection of the guy he once was: an aspirational young man whose sole goal in life is to serve in the Defense Force. Sadly, a strange event involving a rogue kaijuu soon involves the two. Even though Kafka shows his inherent heroism and saves Reno from probable death, he suffers serious injuries in the process.

After being cruelly killed, Tomokui Kanata reincarnates as a goblin in a fantasy realm. Despite coming from lowly beginnings, he has the rare capacity to evolve by devouring other monsters, which makes him stronger. Determined to live and exact revenge on those who killed him, Tomokui sets out on a quest to increase his strength.

Despite his expertise and obsession with magic, Prince Lloyd de Saloum was a commoner in a previous life and was unable to become skilled at it. He is now reborn into his present royal lineage and is endowed with a body that seems to have infinite mana, fulfilling his ambition to become an arcane master. Furthermore, Lloyd is free to develop his skills as freely as he pleases because, as the seventh prince of the country, he has no claim to the throne. Regretfully for Lloyd, the peace is in jeopardy as old seals that hold strong demons begin to malfunction and leak the horrors inside. Lloyd's incredible magical abilities are the only thing that can stop these monsters from terrorizing the area before everything collapses.