Su Nian looked at the girl's wrist. She could see a large, black insect constantly moving about inside the girl's body.
Su Nian recognized this type of insect. It survived by feeding on human blood. While it might indeed consume some body fat, it wouldn't be so well-behaved as to eat only fat.
It would lie dormant inside the human body, slowly devouring blood, then the internal organs, and finally the skeleton. Once it had consumed a person entirely, this Gu would die from overeating.
That's why it's also known as the greedy eating Gu—and it eats people!
Seeing how thin and weak the girl was, so much so that she could barely hold the peach steady, Su Nian said, "Hold out your hand."
Su Nian had already figured it out. The insect would wander all over, so she firmly grasped the girl's wrist and began to wait for the right moment.
As soon as the insect came near, she would use a small blade to force it out.
