The two-day countdown illustration is by Tae Tono, the mangaka responsible for spinoff manga That Time I Got Reincarnated as a Slime: Trinity in Tempest.
Let’s start with the three-day illustration, which comes from Slime spinoff manga author Shizuku Akechi, who writes and illustrates Tensei Shite mo Shachiku Datta Ken (That Time I Got Reincarnated (Again!) as a Workaholic Slime).
Tomorrow marks the long-awaited return of the That Time I Got Reincarnated as a Slime anime, so the staff behind the production has been building up to it with some awesome countdown illustrations by Slime spinoff manga artists.