The Loneliness of Competition

Gretel passed through the energy channel and landed on a high-energy continent. After hard training, the energy star sky collapsed and he became an ordinary person again. This continent has a splendid agricultural civilization, but due to the lack of gold, silver, copper, iron, tin and other metals, the civilization stopped in the Stone Age. How to survive and evolve in this lonely civilization has become Gretel's biggest question. We have the ability to tap the potential of civilization, resist the ravages of nature, and resist wars between civilizations at the same level. However, how to develop to resist the invasion of foreign civilizations, even iron civilizations? The second brain didn't figure out the answer before it was broken, so it could only be left to the lonely Gretel to try.