Rentt Faina, a 25-year-old adventurer, has been hacking away at monsters for a decade. Without much talent for the job, Rentt finds himself stuck hunting slimes and goblins for meager amounts of coin every day. Little does he know, all this is about to change when he comes across a seemingly undiscovered path in the Water Moon Dungeon. What awaits him at the end of the path, however, is neither treasure nor riches, but a legendary dragon that wastes no time swallowing him whole! Waking up a short time later, Rentt finds himself not quite dead, but not very alive either―He is nothing more than a pile of bones! Armed with nothing but his trusty sword, tool belt, and ghoulish new looks, Rentt sets off on his quest as a newly reborn skeleton to achieve Existential Evolution, hoping to one day return to civilization with a more human form. Will Rentt succeed, or will the dungeon consume him for the rest of his un-death...?

Even though Sasaki's droll corporate life is constantly filled with work, it leaves him tired and unfulfilled at the end of every day. In search of some companionship to fill the emptiness in his life, he visits a pet shop on a whim, not realizing he's about to change his life forever. After settling on an adorable bird and bringing it home...his new roommate reveals that it's actually an incredible sage from another world who promptly bestows Sasaki with supernatural powers as well as the ability to cross between worlds. All Sasaki wants to do is use these newfound powers to live in peace and comfort, but there are more than a few colorful characters who might get in the way of that...

After his high school graduation, Yuuki Wakura realizes it has been five years since his sister's disappearance during a "Mato disaster." Throughout Japan, mysterious entrances have opened to a dimension called "Mato"—a demonic metropolis filled with disastrous monsters known as the "Shuuki" that threaten the safety of humans. However, a new hope arose, as the discovery of a Mato fruit that grants supernatural abilities exclusively to women allowed them to fight against the Shuuki. Due to this, a new matriarchal government was formed, establishing a female organization called the Anti-Demon Corps, which caused men to fall to the bottom of society. When Yuuki suddenly finds himself in Mato, he is unable to escape on his own. But just as he anticipates a gruesome end by the Shuuki, a girl in a militia outfit appears and protects him. As the chief of the Seventh Unit of the Anti-Demon Corps, Kyouka Uzen is ambitious yet devalued by her own peers due to her power being deemed unusual. Now in a life-or-death situation, Kyouka takes the opportunity to find out the true potential of her superpower by using Yuuki: in order to defeat the Shuuki, he has to become her slave.

Awaking to absolute chaos and carnage while on a school trip, Yogiri Takatou discovers that everyone in his class has been transported to another world! He had somehow managed to sleep through the entire ordeal himself, missing out on the Gift — powers bestowed upon the others by a mysterious Sage who appeared to transport them. Even worse, he and another classmate were ruthlessly abandoned by their friends, left as bait to distract a nearby dragon. Although not terribly bothered by the thought of dying, he reluctantly decides to protect his lone companion. After all, a lowly Level 1000 monster doesn't stand a chance against his secret power to invoke Instant Death with a single thought! If he can stay awake long enough to bother using it, that is...