Xu Xin and his team had been staying inside the World Tree for so long, but only three or four days had passed outside. During these few days, the growth rate of those creatures was indeed very fast, and their size had already doubled.
But even doubling their size wasn't enough.
If they had a few months, they might grow into giant beasts in Crystal City.
But now, where do Xu Xin and his team have a few months?
Who knows when the alien invaders will attack...
The World Tree has it, but Crystal City can't be moved to the World Tree.
"That's right, with the nurturing of Crystal City, those mutant creatures grow too slowly. By using this acceleration, they can quickly grow into giant beasts in a short time, guarding the surroundings of the World Tree! We used this method when we cultivated giant beasts initially."
