As he's living out his amazing slime life, Rimuru decides to record his experiences in a diary... but there are so many, he doesn't know where to start. That's just how life in Tempest goes.

As the seasons turn, Rimuru plans a Bon Festival celebration. Each race has its own history, and the festival is a time to show gratitude and reaffirm their bonds among their own families and clans, and to strengthen friendships by telling others all about their own histories. And with this Bon Festival, Shizu-san returns to Tempest as a spirit...