King in Exile

Qin Yi, who was once the king of a country, took off his crown and "left" the world where magic existed. When he returned to the earth and planned to start a life that a normal person should have, the humans who lived in settlements, wore rough and inferior handmade clothes, were hungry, and the ruins of the city that had collapsed long ago made him give up his original idea... In the past, humans suffered both losses in the war with omnics. After humans, who were highly dependent on omnics, lost the assistance of machines, the outstanding modern civilization rapidly declined back to the primitive Iron Age. Everything in the world must decline when it prospers. Qin Yi realizes that human civilization on earth is in danger. He decides to use the knowledge and rewards he gained from his adventures in another world to restore mankind's past glory.