Tensei shitara Slime Datta Ken 4th Season

With Tempest thriving after its grand opening festival, Rimuru moves closer to the world he wants to build, one in which humans and monsters can cooperate as equals. That success also makes his nation impossible for old powers to ignore. Granbell Rozzo, a former Hero and influential western leader, and his granddaughter Mariabell begin weaving schemes intended to control emerging powers in the name of protecting humanity.

Tempest is drawn into a political and magical struggle involving Mariabell's ability to manipulate others, Demon Lord Leon's movements, and factions operating behind several layers of deception. As signs point toward the awakening of another Hero, Rimuru discovers that building a prosperous country was the easy part; convincing a fearful world to let it exist may demand battles against the people who profit most from that fear.