Trinity in Tempest Volume 4

Trinity in Tempest Volume 4 is the fourth volume of the That Time I Got Reincarnated as a Slime: Trinity in Tempest spin-off manga adaptation.

Synopsis
THE DEMON LORD RISES!

So many monsters have lost their lives at the hands of the Falmuth army! Phos and the rest of the Trinity feel guilty for failing to protect them. Lord Rimuru, bereft because of Shion's death, secludes himself for four days, then makes a momentous announcement. "I shall become Demon Lord!"

Chapters

 * Chapter 17: To Be Announce.
 * Chapter 18: To Be Announce.
 * Chapter 19: To Be Announce.
 * Chapter 20: To Be Announce.