That Time I Got Reincarnated as a Slime: Trinity in Tempest (manga), Volume 7

The battle against the Demon Lord Clayman has come to an end. The leaders of Tempest, Eurazania, and the City of the Forgotten Dragon are busy dealing with the aftermath when they receive troubling news from Claire of Fulbrosia. Frey and Carrion have both formed an alliance with Milim Nava. With the trinity and their respective homelands united, the three warrioresses must adapt to the world that is changing around them whilst under the veils of this new threat.