That Time I Got Reincarnated as a Slime manga volume 19 features story by Fuse with illustrations by Taiki Kawakami.

At the climax of the Walpurgis, Clayman’s schemes are exposed, and he resorts to desperation. Although Rimuru is firmly in command, this is unlikely to be the end of the Moderate Harlequin Alliance. Meanwhile, the truth about a certain vampiric Demon Lord with connections to the Holy Church are sure to complicate matters for Tempest. The origins of Luminism are finally revealed!