The Overlord of Time and Space Through Time Travel

Quan Shuangwen (double world travel + farming + territory development + hegemony in another world) Li Ming is a modern man who can travel back and forth to an ancient world of fighting spirit and magic. He landed in this mysterious land, became a prince, and owned a fief. Li Ming decided to use his modern knowledge to develop the fiefdom and establish his own power. He used modern agricultural techniques and seeds to increase crop yields and ensure adequate food supply in the fiefdom. At the same time, he also used modern industrial knowledge to build fortifications. Because Li Ming can travel to the modern world at any time and acquire modern weapons and technology. He brought back advanced firearms, tanks and aircraft, and used these modern weapons to dominate the magical world of fighting spirit. And was named His Royal Highness the Crown Prince. The development empire grew stronger step by step. What? You are a third-level Douqi master. Look at my 81-bar rifle. What? You are a level five fighting spirit master, look at my rockets. What? You level 7 Dou Qi master, look at my Dongfeng missile. Ah! You are a level nine Dou Qi master, so what weapon should I use?