That Time I Got Reincarnated as a Slime, Vol. 18 (light novel)

ANGELS AND DEMONS AND MONSTERSThe seraphim force led by Michael proceeds with its plans for invasion, and the Octagram’s eight demon lords assemble once more for a Walpurgis Council to determine their response. They need to act fast, for Michael’s Ultimate Dominion skill has brought even Velzard—a True Dragon and Veldora’s eldest sister—under his control. How will they solve this conundrum? Rimuru isn’t sure yet, but as he readies Tempest for war, he’ll soon discover a lot of his problems are much closer to home than he thought