Manga Volume 17

 is the seventeenth volume of the manga adaptation of That Time I Got Reincarnated as a Slime.

Synopsis
A JOURNEY INTO HELL

Now that Rimuru has risen to the level of Demon Lord, the pinnacle of monsterkind, the powers of the world inevitably take notice. Foremost among them are the other Demon Lords, who call a meeting known as a Walpurgis, a space for these fearsome figures to hash out their differences. Though Rimuru secures an invitation to the event, he must tread carefully until he can distinguish friend from foe…

Chapters

 * Chapter 75: Monster-and-Man Summit II
 * Chapter 76: Demon Lord and True Dragon
 * Chapter 77: Eve of Battle
 * Chapter 78: Walpurgis
 * Chapter 79: Battle