After the broadcast of the final episode of That Time I Got Reincarnated as a Slime Season 3 on September 27, it was announced that the popular series will receive both a second theatrical film and a fourth season of the TV anime. This announcement was accompanied by an official illustration showing Rimuru with a determined expression, with his eyes particularly emphasized. Additionally, teaser material for the new film and TV season was released.

That Time I Got Reincarnated as a Slime tells the story of Satoru Mikami, an office worker who is fatally stabbed and reincarnated as a slime in another world. The series has been broadcast in multiple seasons: Season 1 in 2018, Season 2 in 2021, and Season 3 in 2024. The first film, That Time I Got Reincarnated as a Slime: Scarlet Bond, was released in November 2022. The original manga, written by Fuse and illustrated by Taiki Kawakami, is currently serialized in Monthly Shonen Sirius (Kodansha).