After the climactic battle to decide the fate of humanity, the hero Max, alongside his party, emerges victorious against the formidable Demon Lord. As he draws his last breath, the defeated Maou vows to return more powerful than ever to take his revenge. Ten years later, although Maou has resurrected, the process is incomplete, resulting in him taking on the form of a child. Nevertheless, not wanting to waste another second, Maou pays his nemesis a visit—but the hero who once gallantly protected humankind from the demon's clutches is now a pitiful slob bearing no resemblance to a man of his former caliber. Despite his disappointment, Maou moves in with Max in hope of building him back up into a worthy adversary. But as the demon learns more about the events that transpired in the decade of his absence, he realizes that there is a story behind Max's downfall that he knows nothing of.

Video games, especially puzzle games, were always at the center of Konomi Kasahara's life. However, upon entering Hanamiya High School, she decides to break away from this lifestyle. As Konomi wanders the halls in search of a new activity to engage herself in, she stumbles upon a gigantic wall owned by the school's rock climbing team. Fascinated, she attempts to scale the wall, discovering that she can use her puzzle-solving skills to help her reach the top. Certain that she has found her calling, Konomi immediately joins the club. As she strives to improve her climbing skills, Konomi, alongside the rest of the Hanamiya Climbing Team, will learn what it truly means to be a "sports climber" and work to achieve victory in the upcoming competitions.

Having reached the pinnacle of human potential, Varvatos was so powerful that the rest of humankind began calling him the Demon Lord, both fearing and respecting his overwhelming influence. As a result, he felt alienated from his fellow humans, leading him to desire true companionship—an equal he could call a friend. Hoping his fate will change in his next life, Varvatos decides to start anew and reincarnates three thousand years later as Ard Meteor, the son of a seemingly ordinary couple in a rural town. Unfortunately, he realizes that even after weakening himself, his strength still overshadows everyone in this era. Moreover, his lack of social skills bars him from achieving his goal of making friends. But worst of all, the repercussions of suddenly abandoning his former position have begun to bite him back in some of the most unimaginable ways possible.