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.
to declare himself a Demon Lord 
and destroy Falmuth when they attacked...
لتنصيب نفسه سيّد شياطين وتدمير
...فالموث عندما شنّوا هجوماً
para se declarar um Lorde Demônio e
destruir Falmuth quando eles atacaram...