That Time I Got Reincarnated as a Slime is a Japanese isekai fantasy franchise that began as a web novel and expanded into light novels, manga, anime and other media. Its Japanese title is sometimes presented as 転生したらスライムだった件 and the Hepburn romanization as Tensei Shitara Suraimu Datta Ken. The story centers on a modern-day man who is reborn in a fantasy world as a lowly slime creature, rapidly acquires unusual abilities and adopts the name Rimuru Tempest. The plot blends adventure, comedy and political world-building as the protagonist creates alliances, founds a nation and encounters a broad cast of monsters and humanoid peoples.

Core concept and characteristics

The premise subverts a typical isekai trope by making the protagonist an initially weak, amorphous being with a wide range of evolving powers rather than a conventional human hero. Themes include transformation, cooperation between races, diplomacy, and the practicalities of running a fledgling state. The narrative often alternates between action sequences and slower passages focused on governance, technology transfer and cultural exchange, giving it a distinctive mix of episodic encounters and long-term plot development.

Publication history and development

The work began as a self-published web novel released on the user-submitted platform Shōsetsuka ni Narō. It was later picked up for formal publication as a light novel series with illustrations by Mitz Vah; the print edition was published by Micro Magazine, and the series has seen numerous volumes released in Japan. The light novel line has been licensed for English release by Yen Press. For information on the original light novel run, see the light novel edition.

  • Several manga adaptations interpret different portions of the story and are published by major houses; a principal manga adaptation is available through Kodansha — see the Kodansha manga.
  • Spin-off manga and side-story titles have been serialized by other publishers, including works tied to Micro Magazine that explore secondary characters — see spin-offs and extras.
  • An anime television adaptation produced by the studio Eight Bit brought the series to a wider international audience; additional seasons and related animated productions followed — see details at the anime adaptation.

Beyond printed and animated forms, the franchise has inspired audio dramas, stage events, merchandise and video game tie-ins, a common pattern for commercially successful contemporary light novel properties. Its mixture of character-driven episodes and large-scale political arcs makes it adaptable to both episodic and serial media.

Notable about the series is its focus on nation-building and diplomacy from the viewpoint of a non-human protagonist: rather than solely pursuing combat-focused progression, much of the plot examines the logistics of creating a multi-species community and the moral choices that accompany leadership. This emphasis helped the work stand out during a period of booming isekai titles and contributed to broad mainstream popularity, leading to international licensing and translations.

For readers wanting to explore the franchise across formats, the light novels provide the original narrative foundation, the various manga offer visual retellings and side stories, and the anime presents a condensed, animated version of major arcs. Each medium highlights different aspects of character development, world-building and tone, allowing fans to approach the story from multiple angles.

Further information, release schedules and official announcements are typically published by the original publishers and production studios; check publisher notices or official franchise channels for the latest updates.