A decade ago, princess Krystal Novaty “Hime” Nokanatika traveled from another world to escape assassination attempts by an evil force. When she arrives in modern-day Japan, she encounters Haruto Satou. With him she shares a promise: he must forget what he has just witnessed, and the two will become friends. Now heading back to the Nokanatika Kingdom to fulfill her royal duties, Hime bids farewell to Haruto. However, when the young man suddenly remembers his first meeting with Hime, he rushes to the location where she first appeared and crosses the dimensional portal to be reunited with her. His arrival disrupts the marriage ceremony between Krystal and prince Marmarugias Gisaras. The wedding is brutally interrupted by the attack of an abyss monster who threatens the princess' life. Acting impulsively, Hime decides to exchange rings with Haruto, which grants her new husband light powers that permit him to slay the monster. Now dubbed as the Ring King, Haruto must marry four other princesses to acquire new magical powers and have a chance to prevail in his fight against the enemy of the world: the Abyss King.

After the demise of the demon king, the resulting power vacuum has broken the balance of the world. Eager to claim this power for themselves, self-proclaimed demon kings from various worlds assemble in the New Principality of Lithia to fight for it. Among them, master swordsman Soujirou Yagyuu seeks to take this coveted position for himself. Joined by Tooi Kagizume no Yuno, a young girl he saved from an army of golems that destroyed her city, Soujirou enters Lithia to battle his way to the title. At the same time, the leaders of the Aureatia Kingdom seek to destabilize Lithia by launching bandits after the convoys of merchandise transiting through the principality. Enraged, Imashime of Taren, the founder of Lithia and defector from Aureatia, sends vicious thief Kasasagi no Dakai to investigate the origin of these attacks. With war on the brink of eruption, no one can predict what influence the contenders for the demon king's throne will have on the coming conflict.

Twenty-seven-year-old salarywoman Midori Akitsu suddenly dies in her apartment due to overwork. As her spirit leaves her body, God appears before her, offering Midori a second chance at life in another world called Asdyllon. There, she must observe how badly humans persecute other species and judge if they should continue existing. To help her get started, God grants Midori a special ability: to be liked by all kinds of non-humans—whether it be animals or holy beasts—enabling her to embrace and cuddle them as much as she wants. Now reborn as Nefertima Osfe, a duke's daughter, she enjoys her new life to the fullest alongside her adorable companions. However, it will not be long before she discovers what her task truly entails and that her time in this world will not always be fluffy.

After his relationship with Eris Boreas Greyrat reaches new heights, Rudeus Greyrat is ecstatic. Unfortunately, his joy is short-lived, as Eris suddenly abandons him to embark on her own journey. Believing that Eris has lost all interest in him, a heartbroken and depressed Rudeus sets forth to the Northern Territories. With his sole goal being to locate his mother on the vast continent, Rudeus wonders if persisting through daily life is worth the pain, falling into a robotic routine as he endlessly ruminates on his lost love. However, the dangers of the North soon prove that one cannot survive with a dulled mind. While on a quest with the party Counter Arrow, with whom he recently became acquainted, Rudeus has a brush with death—an experience that forces him to finally snap out of his despair. With his newfound teammates, Rudeus rediscovers the pleasure of daily adventuring and moves forward with his original goal of living his second lease on life to the fullest.