Manga Volume 14

 is the fourteenth volume of the manga adaptation of That Time I Got Reincarnated as a Slime. The special edition of this volume is bundled with an OAD.

Synopsis
REVENGE SERVED COLD

The hostile human nation of Falmuth staged a devastating attack on Tempest, the peaceful land of monsters. Now, in order to bring back the dead and protect the living, Rimuru is determined to become the most feared of beings: a Demon Lord. But this evolution comes at a terrible price, and the assailing humans will soon realize how poorly they've chosen their enemy...

Chapters

 * Chapter 64: Difference in Class
 * Chapter 65: Megiddo
 * Chapter 66: Merciless
 * Chapter 67: The Worshipping Demon

Bonus Short Story:
 * Veldora's Slime Observation Journal