Different World Alchimaira: The Weakest King and Matchless Army

The VR game "Tactics Chronicle" is a kingdom-building game. One day, Helian, a top player as the king of a land of demons, was suddenly transported into the game world itself. And there he found the game characters ruling the kingdom in his name...! This is the epic story of a weak human king who will lead a mighty army of warriors and demon-beasts to conquer a fantasy world!

(Source: Gangan Online, translated)