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.
That Time I Got 
Reincarnated as a Slime
ذلك الوقت الّذي خُلِقتُ فيه من جديد كهُلام
 Meine Wiedergeburt als Schleim 
 in einer anderen Welt 
That Time I Got
Reincarnated as a Slime
That Time I Got
Reincarnated as a Slime
MOI, QUAND JE ME RÉINCARNE EN SLIME
That Time I Got Reincarnated as a Slime
That Time I Got
Reincarnated as a Slime
О моём перерождении в слизь