After a disastrous romantic confession, Masamune Okumura finds solace in the fictional world of anime and manga. Now a second-year high school student and the president of the Manga Research Club, Masamune spends a peaceful existence watching the adventures of the angel Liliel, his favorite character. In the beginning of the academic year, Masamune’s life is turned upside down when he meets first-year student Ririsa Amano, a passionate cosplay practitioner. Despite Masamune's initial reluctance, the determined young woman manages to convince him to become her personal photographer for the production of a collection dedicated to their common favorite character: Liliel. As Masamune enthusiastically discovers the world of cosplay and photo editing, he is unexpectedly reunited with his childhood friend Mikari Tachibana, who has become a model in the hope of impressing her beloved upperclassman. Realizing that modeling is not enough to intrigue the hopeless otaku, Mikari decides to join the club and become a cosplayer herself, all to finally have a chance at winning Masamune's heart. However, Masamune's love for fictional characters may not be capable of extending to those who impersonate them.

After Yang Wen-li successfully captures the Iserlohn Fortress, the Free Planets Alliance grows bolder in its militaristic ambitions. With recent incursions into Galactic Empire territory and the possession of a perfect beachhead, the Alliance is now able to deal significant damage to the Empire. However, Reinhard von Lohengramm has no intention of allowing the Free Planets Alliance to gain a foothold. He is adamant about carrying on his best friend Siegfried Kircheis' dearest wish: to be the one to unite the universe. As wide-scale military clashes continue, the opportunist Adrian Rubinsky, Fezzan's ambitious leader, attempts to take advantage of the war to further his personal goals.

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.