Ryō Ariyama is the original creator of the light novel series Romelia Senki, also known as Romelia War Chronicle. Ariyama began writing the story as a web novel, serializing it on the user-generated novel publishing site Shōsetsuka ni Narō starting in August 2019. The series gained enough popularity to be acquired by the publisher Shogakukan, which began releasing it as a light novel in June 2020 under its Gagaga Books imprint, with illustrations first by Kodama and later by Ryō Kamito from the second volume onward. The light novel series, which is scheduled to conclude with its sixth volume, has been published in five main volumes and one side story volume.

The success of the original light novel led to a manga adaptation, for which Ariyama is credited as the original creator, with art provided by Ryō Kamito. This manga began serialization in April 2021 through the Manga Doa app and has been collected into multiple tankōbon volumes by Mag Garden. The manga has also been licensed for an English-language release by Seven Seas Entertainment. The story has expanded further with the announcement of an anime adaptation in September 2024, solidifying Romelia Senki as Ariyama's most significant and widely recognized work.

The narrative of Romelia Senki blends elements of fantasy, action, and military science fiction, centering on the protagonist Romelia in the aftermath of a demon king’s defeat. The series has seen commercial success, with over 400,000 copies in circulation as of September 2024, marking Ariyama’s entry into the professional publishing industry and establishing a multi-platform media franchise that spans web novels, light novels, manga, and an upcoming anime adaptation.