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

The 72nd Demon King, Astaroth, has been reincarnated in a strange new land with a mission 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 his rivals, but he won't hesitate to use all the means at his disposal to achieve victory. Wielding unheard-of resourcefulness and tactics, he'll reshape the fate of all who live under his reign!