That Time I Got Reincarnated as a Slime: 0x14

Digression: Diablo's Journal

After defeating Clayman at Walpurgis, Rimuru officially became a Demon Lord and a member of Octagram. Meanwhile Diablo awaits Rimuru’s return in Tempest, and is anxious to learn about his master’s activities as soon as possible. A look back at Walpurgis.