The alien invaders' weakness is their "Source of Life," the red crystal.
A substance they have been seeking for tens of thousands of years, a hope of racial continuation.
Now, a large amount of this material is being stored on Earth.
Because on Earth, there is enough of the raw material for their entire race to continue for tens of thousands of years, a large number of alien invaders need to station here for extraction.
"I say, wasn't the red glow that appeared during your invasion of Earth, causing Earth creatures to mutate, also related to your red crystals?" Xu Ying asked.
"Yes, the ammunition for that ray weapon was precisely those red crystals."
The monster explained.
"Because of the threat from Earth's humans, they decided at that time to destroy Earth's humans at all costs, so they used this method to induce mutations in half of the planet's creatures to attack the other half."
