The Reformation of the World as Overseen by a Realist Demon King, Vol. 1 (manga) — Ryosuke Hata

Astaroth has been reincarnated into a strange new land as the seventy-second Demon King with a mission from a mysterious goddess to unite the world under his banner and reform its chaotic ways. As the youngest of the demon kings, his forces may be weaker than those of his rivals, but he'll sink as low as he must to achieve victory. As Astaroth rises through the ranks, utilizing deception and trickery to crush his foes, he'll reshape the fate of all who live under his reign!