Tensei Shitara Slime Datta Ken: Ibun - Makoku Kurashi no Trinity

Tensei Shitara Slime Datta Ken: Ibun - Makoku Kurashi no Trinity, known as The Slime Diaries: Trinity in Tempest, is a spin-off manga series that expands the world-building of the popular light novel franchise authored by Fuse. Launched in 2019, the series was created to provide a more detailed look at the daily lives of residents within the Jura Tempest Federation, focusing on the perspective of three specific characters—Foss, Stella, and Nimu—who arrive from the Beast Kingdom of Eurazania. This perspective allows the narrative to explore the socio-political development and the mundane, humanizing aspects of Rimuru Tempest's nation that are often sidelined in the main plot.

The illustrations for the spin-off are handled by Tae Tsuiseki, who was tasked with maintaining the aesthetic continuity of the franchise while capturing a slice-of-life tone. The series is published under the Micro Magazine banner, mirroring the serialization approach of its parent work. It has been generally well-received by the existing fanbase for its contribution to the expanded universe, offering a quieter, character-focused contrast to the high-stakes battles that define the primary light novel series.