Entering the 22nd century, Earth has mastered solar energy and applied it to every household, resolving the so-called energy crisis.
Even before solar energy was skillfully applied, Earth had many energy sources to utilize.
Coal, gasoline, natural gas, biogas, wind energy, hydropower, etc.
All in all, humans on Earth now seem never to have worried about energy, although in the 21st century, many humans clamored about an energy crisis.
A mysterious voice said, "The energy we need is completely different from the energy you need."
"You should know very well, we are different from you. To strengthen ourselves, we plunder various energies on Earth. Long ago, Earth also had Spiritual Qi, but it was absorbed completely by us, along with a thousand-year Zhu fruit, Water of the Underworld, thousand-year-old ginseng, and other heavenly resources."
"After our endless exploitation, Earth's various resources have been depleted."
