That Time I Got Reincarnated as a Slime now has a spinoff yonkoma manga! It’s different from the main story, and tells the story of Rimuru and friends in their daily lives. Milim Nava, one of the Great Ten Demon Lords, makes her appearance here! While she enjoys her stay in Tempest, Rimuru and the residents of Tempest look after her warmly sometimes and nervously others.
- Diary 9: The Demon Lord Has Arrived!
- Diary 10: Fall Harvest
- Diary 11: The Arrival of Winter
- Diary 12: Where's Santa Claus?
- Diary 13: Enjoying the New Year
- Diary 14: A Blanket of Snow Upon the Town
- Diary 15: Before the Wind Blows
- Diary 16: Total War for Tempest
- Diary 17: In a Sakura Blizzard