That Time I Got Reincarnated as a Slime: Coleus' Dream has revealed its key visual, also announcing that the ending theme song will be performed by Miho Okasaki, the voice actress of Rimuru. The OVA series, scheduled for premiere in fall 2023, is based the original short story included in the Blu-ray release of the anime's second season.

The story of That Time I Got Reincarnated as a Slime: Coleus' Dream follows Rimuru, who receives a request from Yuuki Kagurazaka to investigate the truth behind the succession conflict in the Kingdom of Coleus, a principality situated between the Kingdom of Ingrassia and the Holy Empire Ruberios. Disguised as the "Great Phantom Thief Satoru", Rimuru begins his undercover investigation, but things are not as simple as they seem. The involvement of demons and vampires makes the situation more chaotic than he had imagined.

• STAFF
• Original by: Fuse & Taiki Kawakami
• Directed by: Atsushi Nakayama
• Series composed by: Toshizou Nemoto
• Characters designed by: Ryouma Ebata
• Studio: 8 BIT