The Octagram Soars Brightly

The Octagram Soars Brightly (八星輝翔編) is the sixth volume of the That Time I Got Reincarnated as a Slime Light Novel.

Synopsis
A MEETING OF DEMONIC MINDS!

Newly minted demon lord Rimuru has received word of a special assembly of all ten demon lords known as the Walpurgis Council. It just so happens that the topic of this particular meeting is how best to punish Rimuru for assuming their new title without their permission.

Fortunately, they've got friends in high places who are willing to vouch for Rimuru's authenticity, and this council could be the perfect opportunity to get revenge on the demon lord Clayman for the violence he brought to Tempest. Is this blobby big shot cunning enough to kill two birds with one stone?

Chapters

 * Prologue: The Magic-Born's Ruse
 * Chapter 1: Between Monster and Man
 * Chapter 2: Word from Ramiris
 * Chapter 3: The Eve of Battle
 * Interlude: The Demon Lords
 * Chapter 4: In the Land of Destiny
 * Chapter 5: Walpurgis
 * Chapter 6: The Octagram
 * Epilogue: In the Holy Land

Adaptations
This volume was adapted into the following material:

Manga:
 * Manga Volume 16
 * 73: A Conspiracy of Majin
 * 74: Monster-and-Man Summit I
 * Manga Volume 17
 * 75: Monster-and-Man Summit II
 * 76: Demon Lord and True Dragon
 * 77: Eve of Battle
 * 78: Walpurgis
 * 79: Battle
 * Manga Volume 18
 * 80: Return of the Beast
 * 81: Wight King
 * 82: A Demon's Loyalty
 * 83: The Crazed Clown
 * Manga Volume 19
 * 84: Moderate Clown Troupe
 * 85: In a Holy Place
 * 86: The Octagram

Anime:
 * Episode 37: The Visitors
 * Episode 38: A Meeting of Humans and Monsters
 * Episode 39: Ramiris's Warning
 * Episode 40: The Congress Dances
 * Episode 41: The Eve of Battle
 * Episode 42: The Demon Lords
 * Episode 43: The Signal to Begin the Banquet
 * Episode 44: On This Land Where It All Happened
 * Episode 45: Adalman, the Index Finger
 * Episode 46: Demon Lords' Banquet ~Walpurgis~
 * Episode 47: Returning from the Brink
 * Episode 48: Octagram