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.
A very special event that 
all Demon Lords attend!
!حدث خاصّ جدّاً يحضره كافّة أسياد الشّيطان
Um evento super especial de que
todos os Lordes participam!
Особое собрание,
куда приходят все Князья!